iCal.py
Apple doesn't document the API for interfacing with iCal, but it does save it's files as industry standard iCalendar files . I went looking recently for a python module to interface with iCal, and couldn't find one. But I DID find Rod Schmidt's excellent article for doing the same thing with Ruby.
So, naturally, I ported his solution to Python! It seems to even work!
Anyway, YMMV, no warranty implied. Do with it as you see fit.