Kind of what others have said- much of the of Microsoft lifecam range do quite well (if I have to suggest one it is usually these) and many modern ones do well under quite low light conditions. Colours will probably never match that of a big boy camera but most people have been trained to expect otherwise and colour correction can do OK if you want as well.
The trouble for me usually comes in though they may say 720P at 30fps the effective FPS is somewhere around 13 fps* owing to USB2.0 being somewhat limited in bandwidth** and only the fanciest webcam doing enough real time compression to get around this limit (which also troubles the programs you can capture with). I am not sure what goes with firewire webcams these days but they were the traditional end run around those limits and I imagine USB3.0 webcams will probably rock up and do well before long. It is also one of the cheaper methods Rydian warned you of but things that still claim to work are probably quadrant based (see rolling shutter) so be aware of that, depending upon what goes as long as you are not panning around you should be good.
You might also run into trouble with different colorspaces (YUY2, MJPG and M420 being the big three) and some do gain a couple of FPS over another but eh really- get a proper camera if you have to start thinking about that.
*were we doing a proper video course I might ponder stutter at this point (see bad pulldown and/or decimation or maybe just pulldown NTSC if you have watched PAL all your life) but I am not going there right now.
**I know it is some 25 megs a second but we are dealing with what is effectively raw video so that is nothing.
