Well, most any compact video camera will work," so far as that goes. Sonys DCR HC48 MiniDV camcorder ($500; sony.com) is compact (2.6 x 3 x 4.5 inches) and light (15 ounces) and has excellent video quality thanks in part to its superb Zeiss lens. Panasonics PVGS80 ($279; panasonic.com) offers similar dimensions and the same MiniDV tapes for recording, but without some of the bells and whistles of the Sony. Both offer image stabilization, which could come in quite handy on a bike.
The problem, it seems to me, is mounting it to your bike and getting any meaningful footage out of it. You can look around on the Internet and find examples of how people have rigged handlebar mounts, but you wont find one commercially made (so far as I can tell). Then theres the problem of video quality. For some reason I think youre talking about a mountain bike, and even with front shocks and image stabilizing I dont see anything coming out of this except hours of blurry tape.
As for carrying a camera in a small pack and pulling it out to record key stretches when your friends try themwell, of course, that would work just fine. And thats mostly what you see on YouTube in all those taped cringe-inducing crash videos.
Or, re-think the solution. One possibility is the Digital Hero Camera ($140; goprocamera.com). Its a compact 3-megapixel digital camera that straps to your wrist (or a handlebar). In that mode, its not too much bigger than a very fat watch. Then, to use it, you simply flip the camera up (it attaches to a hinged mount) and press the shutter button. It takes stills and fairly decent (but short) video. Are you going to want to shoot film while bouncing down the local singletrack? Well probably not. But its a very handy thing to have, and it certainly eliminates the hassle of fishing a camera out of a pack.
The Gear Guy reports from 2007 Winter Outdoor Retailer, the bi-annual gearapalooza in Salt Lake City. Check out his top picks for gear to watch in 2007.