Basically, all the search engines will let you suggest the preferred URL you’d like them to focus all the SEO juice on:
To use Google’s example, all you put in the head tag is something like this:
link rel=”canonical” href=”http://www.example.com/product.php?item=swedish-fish”
That’s all there is to it, folks.
Here are the links to the new canonical goodness!
For once, the search engines unite to make and SEO’s life a little easier.