What photo camera do you have now?
A lot of them take very good videos as well.
You could just get any decent compact camera
but the tricky part is the mounting, especially
if you want to place the camera on your head -
helmet. Also with regular cameras you're a bit
limited with the recording time, maybe 15 -30
minutes. This is why some folks get action/sport
specific cameras - GoPro, Contour, etc. They
have longer recording times( a few hours some of them)
and have different mounting options.

Contour GPS mounted on the bars with 2 pieces of inner tube:

Samsung HZ30W camera mounted on the bars w/ Fotopro mount: