I just installed one on my 2005 CTS-V. Works great and it comes with an updated cable for the iTouch and iPhone so they charge properly.
Here is the thread:
http://www.cadillacforums.com/forum.../169484-iphone-integration-2.html#post1909845
Here is the thread:
http://www.cadillacforums.com/forum.../169484-iphone-integration-2.html#post1909845