Ever had an issue with problem with someone who has copied your website? All of it or maybe just some of it! It doesn't matter they took it, without your permission. So today I look at the big advance taken by Google, MSN & Yahoo, and some other friends in early Feb (2009) to help us all out a little.
It's a pretty simple tag really, and it belongs with the META tags in your head script
<link rel="canonical" href="http://andykinsey.com/"/>
Generally the advice is to use this only on dynamic websites, see Matt Cutts initial blog post.
So for example, before url re-writing the links for posts was of the format .com/?p=somenumber in the canonical tagging system this would become .com/ all children would be "owned" by this website.
Warning - becareful use of Canonical tagging especially on large-scale websites, use it incorrectly then your search engine rank can be severely damaged!!! - Not sure? Contact Me for individual advice
Other Options ???
Well yes there are other options, infact in Matts presentation (see his blog linked above) you will see he advises that if you can first exhaust other options in preventing duplicate content, both within your own website and from other websites.
However, since we can't help you with removing duplicates from your own site other than the above tagging system I suggest that you use the following steps.