I just got a GoPro Hero and use it for when I go quading:
http://www.youtube.com/watch?v=NO0fts11E3g
When I'm autocrossing, I use MaxQData. Here's a run from 2009 SCCA Nationals:
http://www.youtube.com/watch?v=PxmHl_Q5Z0E
I use the MaxQData because it has useful information, check out a video with data overlay:
http://www.youtube.com/watch?v=1ys78llwQnA