Motion Detection with iSight/FaceTime Camera I'd like to use my iSight camera to detect motion, and if any motion is detected, record a short movie (until the motion stops) for security purposes
(ok, I want to spy on my cat). 

Is there software available to do this? Free/open is preferable.
I've used iAlertU before: takes a screenshot, not a movie, but it is free.

There is also SecuritySpy which does record movies but isn't free.