Can you tell me exactly what you're looking for as in 'webcam' ?
Does it have to stream live video? or do you just want to connect your dSLR to the pc, and be able to control it from there?
For the first: Sorry, I can't help you there, but for the second, check out 'dslr remote pro
You might find what you're looking for right there.
If you just want a webcam, I suggest you get a normal logitech webcam or something, they're not that expensive, and they still have decent quality for what you'd expect from a webcam!