Check out the SEOMoz Help section:
"Duplicate Page Content
Duplicate Content means there are pages that are identical (or nearly identical) to content on other pages of your site, which can force your pages to unnecessarily compete with each other for rankings.
Here are some things you can do about duplicate pages:
Delete content that is similar on each page.
Add some new and unique content to each page that is on the report. This can be done by adding more information, ideas, product descriptions, or anything that can make it differ from other pages on the domain.
You can also add a rel=canonical to one of the duplicate pages. Here are a few ways to do this:
Add a rel="canonical" link in between the and elements. This should be done on the version of the page you want to be ranking or that non-canonical version of the two (or multiple) pages.
To specify a canonical link to the page http://www.seomoz.org/blog.php?item=seomoz-iscool, create a element that looks like this: <link rel="canonical"href="<a href="http://www.seomoz.com/blog.php?item=seomoz-iscool">http://www.seomoz.com/blog.php?item=seomoz-iscool"/></link rel="canonical"href="<a>
Copy this link into the section of all non-canonical versions of the page, such as http://www.seomoz.com/blog.php?item=seomoz-iscool&sort=fun.
Keep in mind that that canonicals will stop the pages from ranking against each other, but they will still show up as duplicate content from a UI perspective, so we will still count them as duplicate."
Let me know if this answers your questions.
Mike
