There is a comparison of features between SF and Google Code over at Engtech. There is also an article on Newsforge. I have already set up an account and checked in the code for K2 so that I can play a bit... I am currently underwhelmed.
Google announced their Google Code Project hosting service today at the O'reilly Open Source convention. Greg Stein of Apache, SVN and WebDAV fame announced in his session the new service from Google that is targeted at the Open Source Community.
The new service is set up to be a 'sourceforge' like offering, hosted on Google's servers. The new service will integrate subversion, issue tracking, mailing lists, etc into one Google-fied package. This being Google there is a heavy smattering of search technology throughout. The new system will allow you to search your issue tracker and svn for instance.
This new service will be running out of Google Code Hosting.
More to come as time permits.