It seems that all of the initial Google results for \"using subversion with xcode\" are actually just tutorials for installing and configuring svn and Xcode, as opposed to a
I myself looked up for some good resources and one of the best I've found is a quite recent video from the WWDC 2012 :
Sign in here if it's not already the case : https://developer.apple.com/videos/wwdc/2012/
Then there is a video called :Session 411 - Source Control Management in Xcode
It explains how to use version control both with GIT and Subversion. It's really nice !
Hope it helps!