I bought one of these for my brother when skiing:
http://www.launchhelmetcams.com.au/D...-HD170-Stealth
Works reasonably well, no massive complaints. Not perfect image quality but not bad. Nice wide field.
They're more compact than the go pro's. Can mount them on bike handle, side of helmet, goggle strap, etc.
These are a bit nicer in many ways, a little more compact and less noticeable:
http://www.launchhelmetcams.com.au/contour-roam
Roger.