DuckCall is a trivial little utility that I wrote once I realised that I was getting a MacBook Pro, and it had a camera built into it. It updates your iChat or Adium (requires one of the 1.0 betas) status picture with a shot taken from the iSight evey 30 seconds.
It's very crude, and consists of a PyObjC wrapper round a stand-alone binary (to get the picture from the iSight) and a bunch of AppleScript (to set the picture into iChat / Adium) - there's no reason for it to be written in Python at all, and it's far too large as a result, but PyObjC is my 'crazy prototyping' environment of choice.
RequirementsMac OS X 10.5 or later, iSight.
*Previously available here