I recently discovered that the macam project (http://webcam-osx.sourceforge.net/)
has support for the Playstation Eye for PS3. It supposedly has better quality than a standard computer webcam, but I wouldn't know because I don't own any webcams. So I was very happy that it works with Jitter :)
Note: Version 0.9.1 does not have the PS Eye driver yet. For now you need the latest CVS build (check their downloads page) for it to work. The install instructions are in the full download though. You need the quicktime support installed to use it with Jitter.
Someone else out there probably owns one of these, so thought I'd share this info. Have fun!