I owned a Kensington cheap-o cam that worked fine in OS 9, but I could not, for the life of me, find a way to get it to work under OS X. I thought that the Image Capture application may provide some sort of support, but alas, I couldn't find anything that would help me.
I think, in order to get the camera to work, you'd have to have an OS X specific application written for webcams...
I haven't had a chance to mess around and see if it works under 10.1, though... as of 10.0.4, I hadn't found a way to use it other than to boot back into OS 9.