I stole an idea I found somewhere on the web (might have been here actually).
I bought a cheap case and cut a hole in it. Then I riveted on some long velcro straps and jiust like that you have a helmet cam. All you have to do is strap it around the "chin" of a full helmet and ride.
The only con is that its a little awkward to start and stop the camera recording because there's no hole for the start button. If you want to see pics I'll post some later.