PyObjC has been officially released for Tiger. This is a big upgrade, and includes wrappers for some of the new Tiger technologies, better py2app support and a heap of bug fixes.
So if you weren’t happy following the dev release using subversion, you now have no excuses. Oh yeah, and it will still work on 10.3, with some testing done for 10.2 (if you are still using 10.2 and have issues, please use the mailing list to let the developers know of any issues).
I also found a nice article if you want to start right from the beginning of almost no development knowledge at all for creating Python based Objective C applications. Assumes no knowledge of XCode or Interface Builder (IB) or python for that matter.
For something more interesting, xml.com have a very good article, Unicode Secrets by Uche Ogbuji, which explains how to use unicode properly in Python. Essential reading if you have even vague thoughts of ever using XML in an application.