Open source iSightCapture?
3rd link in Google: http://rondam.blogspot.com/2008/07/isightcapture-secrets-revealed.html


  For anyone who has used iSightCapture and has been frustrated by the fact that it's released in object-code only format, here is qt-capture which is not quite as capable as iSightCapture (it doesn't have any command-line arguments) but does basically the same thing. Since it's just a proof-of-concept and not really finished code I've released it into the public domain.