I placed a bulletcam (helmetcamera.com) on the side of the helmet and it fed a Sony HC MiniDV camcorder. There are positives/negatives to this ride recording option. Positive... One can look around for the viewer, bumpy roads don't matter, can work anywhere. Negative... a nasty network of cables/complexity, extra cost, no lens/filters, etc.
For long trips I usually pack light, bring a simple digital camera with a great movie mode, and connect it to the handlebars via a ram mount. I did this when touring the Swiss/Italian Alps last year on a hired Honda, recording images and 13 ride videos here.