There's been a lot of talk about what webcam is good to use with Pear Note. Unfortunately, most webcams available today have very poor quality video when compared with the iSight that comes built into all of our Macbooks. That said, this is not the case with all webcams.
I just acquired a Logitech QuickCam Vision Pro, and the video quality is actually very good. To my eye, it's better than the built-in iSight. The microphone built into it is not bad either, though it's somewhat muddy. I've also found the Mac driver that comes with OS X to be a little buggy, but as long as the video gets started it seems to work fine. Hopefully Apple will improve the driver soon.
That said, it's still the best option I've found. So, if you're looking for an external webcam to use with Pear Note, I'd recommend it.