This post was published more than a few years ago (on 2003-07-13) and may contain inaccurate technical information, outmoded thoughts, or cringe takes. Proceed at your own risk.
I just found iChatUSBCam on VersionTracker, and downloaded it. In combination with my ol' Logitech QuickCam Pro 4000 and drivers from IOXperts, it works like a charm. Woot!
If you're looking for drivers for your USB webcam to use on Mac OS X, try the aforementioned IOXperts or MaCam drivers. Cheers!