Looking for help/tutorials/sample code of using python to listen to distributed notifications from applications on a mac. I know the py-objc lib is the bridge between python
The source code for GrowlTunes might give you some clues here. You'd have to translate from Objective-C to PyObjC, but eh, whatever. :)
GrowlTurnesController.m (Or grab the whole growl source tree and navigate to GrowlTunes so you can see it all in action.: here's a link to the directions on how to get the source