Intro to capping article on ars technica
http://arstechnica.com/guide/audio-visual/videocapturing/vidcap-1.html
I didn't read enough to really form an opinion, but this may be useful. It also suggested using a modified version of virtualdub to get better synch on caps from poor sources (like old VHS tapes) so that may be helpful.

It's a 3-parter, so check back on their site later for the rest.