Here is some great info on how to setup the all in one SEO plugin for a wordpress site.

You can download the All in on SEO wordpress pack here

This is from jacklebond, you can see the original here

All in one SEO Pack Configuration – site settings

From within your WordPress admin, go to the settings area, then select “All in one SEO”. There are a lot of options here, but don’t feel intimidated, we’ll walk through most of them.

Plugin Status With each new update, the developer has chosen to disable the plugin. Presumably, this forces you to review the settings each time, and hopefully avoid any surprises. You’ll need to enable it after you install and again after each update.

CAUTION: misconfiguration of this setting could negativly affect your rankings!
Obviously, if you neglect to enable the plugin after an upgrade, you can expect some issues with your rankings.

Home Title As its name implies, this is where you provide the page title for the “home” of your web site, leave this blank and word press defaults to the site name you defined in your WordPress configuration.

CAUTION: misconfiguration of this setting could negativly affect your rankings!
According to the 2009 SEOMoz.org SEO Ranking factors survey, page titles are one of the most important factors. Entering a bad, or blank title will cause problems for your rankings.

Home Description This box provides the Content for the meta-description tag. Leave this one blank and WordPress does not even give you a description tag. That is bad, be sure to fill this in with a proper site description.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
Page/Post meta descriptions were also included in the ranking survey, but at a lower level. Ignoring or misusing this could impact how well you perform in search results.

Home Keywords
(comma separated)
Even though use of the meta-keywords tag has been degraded over the years, it is still an important part of an overall SEO plan. Add carefully selected keywords here. Leave this blank and WordPress does not add the meta-keywords tag to your page. For best results, place your primary keywords in the front of the list.
Canonical URLS This newly added feature is enabled by default – leave it that way. If you are not familiar with canonical URLs, and would like to be – read thisGoogle webmaster blog post. For the rest of you, just know that this feature helps avoid duplicate content issues with the major search engines. That’s a good thing.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
Duplicate content is a serious issue. Google has said they are less concerned with same site duplication, and are working to understand it better, but they do recommended the use of this tag.

Rewrite Titles If set, all page, post, category, search and archive page titles get rewritten. You can specify the format for most of them (as shown below). For example: The default templates puts the title tag of posts like this: “Blog Category >> Blog Name >> Post Title”. That would be considered anti-SEO. With the default settings, Rewrite Title rewrites: “Post Title | Blog Name”.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
The default behavior of WordPress titles is very anti-seo, use this setting to correct it.

Post Title Format
(other titles too)
Each of the six Title format boxes allow you to customize how the titles are displayed in the various parts of the site. On sites I maintain, I leave all but the Post setting alone. On each of those I insert a few VERY carefully selected keywords (or synonyms). Doing this ensures those keywords are part every title.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
You may be tempted to stuff your titles with keywords. Don’t, it will backfire on you.

Search Title Format This field is confusingly named. It actually has nothing to do with the search engines. Instead, this relates to the results page of your local/site search.
Description Format There are a four automated formats available for the setting. The default is the best one, leave this one alone.
404 Title Format The box sets the page title for your 404 (page not found) error pages.
Paged Format Leave this one alone.
SEO for Custom Post Types WordPress 3.0 introduced the ability to create your own custom post types. If you have created one (or more) and want AIOSEO to be enabled for them, check this box. If not, leave it uncehecked. If you are curious about custom post types, you can read more on the WordPress.orgCustom Post Types pages.
Custom Post Types for SEO Column Support You’ll use this box to list the types of posts you want to have AIOSEO information displayed for while viewing your listings, by default it already includes “posts” and “pages”. If you’ve created a custom post type and want it to have access to the All In One SEO Pack features, be sure and list it here. Unless you really, really dont want to have AIOSEO used on your be careful you don’t delete the default information.
Use Categories for
META keywords
If you are hyper-careful and strategic about your category names, go ahead and use this. If you are like the rest of us, leave this one alone and add your keywords manually for each post.
Use Tags for
META keywords
If you are thoughtful and strategic about your tag names, go ahead and use this as it could save you some time as you create new posts. Checking this causes the tags you set for a given post to be used as the META keywords for that post. You can also manually add additional words as you normally would as well. Just be careful not to duplicate them.
Dynamically Generate Keywords for Posts Page If you have changed the default setting of WordPress and the listing of of your posts is somewhere other than your default/home page then this option determines if you want the keywords for that page set dynamically (based on all the posts listed) or if they should be manually entered. I suggest you do it manually.
Use noindex for… There are three of these boxes, ensure each one is selected. This tells the search engines to not index these areas of your site. This is another method minimizing duplicate content risks.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
If this is not used, you are allowing the engines to index the same content, but at multiple URLs. This is duplicate content, and it’s bad.

UPDATE: If you are correctly using the canonical tag, this is almost a non-issue now. I say almost for two reasons. 1) BING does not officially recognize the canonical tag, and even though they currently are a small(er) piece of the search engine traffic, you don’t want to risk making things worse for yourself in the future. 2) Google likes it when you help them move faster. By telling them they don’t need to index something it allows them to move through the rest of your site more quickly.

Autogenerate
Descriptions
Enabling this feature will tell SEO pack to automagically generate META descriptions for your posts using the first 150 characters of your article. If you are a content rock star and always get your keywords in the first sentence, then this will work great for you. The plugin will look first to see if you set one manually on the post before auto-generating one. Since most of us are note content rock stars, it’s generally safer to enter descriptions manually on each post.

I have this feature enabled to save me a few seconds when I occasionally post articles that I don’t care if they rank or not. It’s also a nice safety net for when I just plain forget to do it.

NOTE: We’ll discuss further down how/where to enter your post and page descriptions.

Capitalize Category Titles This is a bit of a mystery. Check this and page titles, of category pages with be will have the first letter of each word capitalized.
Other than for visual appeal, I (and several fellow SEOs I checked with) can think of no reason to do this. Google’s Matt Cutts, shared with me “Google tends to ignore upper vs. lowercase. But certainly users respond to the differences quite a bit.”The default behavior of WordPress is to use the text you enter as the category title, as the page title as well, if you want initial caps in one, wouldn’t you want it in both?

My recommendation is if you want titles like this, enter them this way and leave this unchecked to save a few processor clicks.

Exclude Pages Pages listed here will not be processed by the all in one seo pack. This is usefully if you have other, non-WordPress, dynamic content running on your site.
Additional Headers There are three of these boxes. Text entered here will be added to the head section of your pages. These are useful if you need to add meta validation for webmaster tools. If you use these, use with caution. These are not required for basic SEO practices.
Log Important Events This is a troubleshooting tool from the developer. If checked and a significant event (No, I have no idea what that would be) happens, it’ll be logged.

All in one SEO Pack Configuration – post settings

When creating a new post you’ll want to scroll to the bottom of your post editing page to the All in one SEO Pack section. There you will see the following four options.

Title You can optionally enter a page title here, if left blank SEO Pack will use the post’s title. If you are attempting to rank in a competitive market (who isn’t) entering an alternate title here allows you to make use of additional keywords or synonyms. Don’t stuff keywords here, you will regret it. Also, the closer your primary keyword is to the beginning, the better.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
According to the 2009 SEOMoz.org SEO Ranking factors survey, page titles are one of the most important factors. Entering a bad, or blank title will cause problems for your rankings.

Description This is the META-description for the post. Carefully craft these as search engines consider them in ranking and display them in results. SEO Pack shows a counter as you type letting you know how close you are to the recommended 160 character limit. Try to get strongest key word/phrase as close to the front as possible.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
Page/Post meta descriptions were also included in the ranking survey, but at a lower level. Ignoring or misusing this could impact how well you perform in search results.

Keywords This is the META-keywords for the post. As mentioned above, use of the keywords tag has been degraded over the years, but it is still used by some engines. Put your most important ones closer to the front.
Disable on this
page/post
If for some reason you wish to NOT use the SEO pack on a page, check this box.

All in one SEO Pack Configuration – page settings

When creating a new page, be sure to update the All in one SEO pack settings, found near the bottom of the editing screen. Page settings are almost identical to the post settings, with just one additional option – menu label.

Title You can optionally enter a page title here, if left blank SEO Pack will use the WordPress page title. Remember, entering an alternate title here allows you to make use of additional keywords or synonyms. Don’t stuff keywords here, you will regret it. Also, the closer your primary keyword is to the beginning, the better.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
According to the 2009 SEOMoz.org SEO Ranking factors survey, page titles are one of the most important factors. Entering a bad, or blank title will cause problems for your rankings.

Description This is the META-description for the page. Carefully craft these as search engines consider them in ranking and display them in results. SEO Pack shows a counter as you type letting you know how close you are to the recommended 160 character limit. Try to get strongest key word/phrase as close to the front as possible.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
Page/Post meta descriptions were also included in the ranking survey, but at a lower level. Ignoring or misusing this could impact how well you perform in search results.

Keywords This is the META-keywords for the page. As mentioned above, use of the keywords tag has been degraded over the years, but it is still used by some engines. Put your most important ones closer to the front.
Title Attribute Text you enter here will become the link title text for links to this page. Link titles appear when you hover over a link. The affect they have on ranking is debatable, but it’s minimal at best. This is more of a usability feature as it allows you to provide additional information about the link. Link titles can add a nice touch if used correctly.
Menu Label The sets the text used in your site menus for this page, left blank it will be the same as the WordPress page title.

CAUTION: misconfiguration of this setting could negatively affect your rankings!
Link anchor text is a VERY powerful SEO tool, use this carefully. This can help a lot, or hurt you badly.

Disable on this
page/post
If for some reason you wish to NOT use the SEO pack on a page, check this box.

 

Be sure to also install the google XML site map site so to adjust the priorities for when google crawls your site. you can get the google xml site map here