Check these guys out if you want serious helmet cam equipment that actually works. http://www.dogcamsport.co.uk/index.html

I have a bullet cam/dvr system on my hover. I find good results from mounting a bullet cam on a monopod which is solidly fixed to some structure such a seat back. Then you can turn the camera in any direction with one hand while driving. The dvr sits in a small pouch on your belt or by your side. Turn the cam on/off with an simple switch on the pouch. I've used it to record hours of cruising and racing footage also by putting the cam in a velcro mount on top of my helmet. 1 4GB SD card lets you record about 4 hours of video. (compressed 640x480 res @30 frames/sec)