We had many requests for URL rewriting support, and although we didn't do a full implementation in the current release, we did add support for short URLs for project home pages. You can link to your project's home page through:

http://www.codeplex.com/<projectname>

So, for example, the home page for the SameDesk project is now:

http://www.codeplex.com/SameDesk

In later releases, we will provide a much richer URL rewriting scheme.