Subversion in Xcode

This page has a good description of using subversion in Xcode 3.0.  The integration works pretty well.

I have found that it is easiest to add a new Xcode project to the subversion repository manually, instead of letting XCode do it.  I just create the project in Xcode, and then on the command line, I run svn add.  Then from that point on, Xcodes integration works well.