Check out the WIA (Windows Image Acquisition) library, which is a COM library that can be accessed rather easily from .NET. There was a good post about it in Coding4Fun quite a while ago, let's see if I can dig it up... there.
This should do it.
Thank you, Yggdrasil, I'll check into it. I'm a little surprised that it takes something extra - as in I'm surprised that the .NET Framework doesn't have something already baked in, to access a PC's webcam.