http://www.bikeforums.net/showthread.php?t=394724
The UK users above use (I think from their reports, youtube pages and UK forums) in decreasing order of preference and expense
vio pov-1
http://www.vio-pov.com/
archos helmet cam (unsure of model) -
http://www.archos.com/products/imt/a...ng=en&p=helmet
ATC-5k
http://www2.oregonscientific.com/sho...cid=14&pid=896
ATC-2k
http://www2.oregonscientific.com/sho...cid=14&pid=709
Public filming with a helmet camera falls under the leisure filming exemption in the UK apparently, i.e., no permission required.