In issue 27 of Velovision ( www.velovision.com ) is an article about helmet cameras.
The safety angle was a new aspect for me…. Just use a 2 Gigabyte memory-card during your ride and if nothing happens, just delete it. But if you register a dangerous traffic-situation on your camera, you have the best means to bring this matter public.

Velovision, originally uploaded by wim harwig.