Thanks to a contribution by Katsushi Kobayashi, VLC 1.2 will support capturing video input signals from all QuickTime-compatible devices. This is basically your internal iSight (which was supported since VLC 0.9) plus any compatible webcam, FireWire video device, etc. The GUI was slightly updated to reflect this change and will get a few more options and refining until the release later this year.
In case you’re interested, this update will be available for testing in tomorrow night’s nightly builds.
Updated: new screenshot with close-to-final layout here.