If you get a helmet cam, you have to make absolutely sure your videocamera has an aux INPUT as well as an aux OUTPUT jack or you are out of luck (and right now, there are literally less than a handful that do). Samsung makes a "sportscam" with a nice external cam that I like a lot, but it records onto memory sticks, so you get limited length of video (25 mins on high res).
Here's another option...and I agree with the above posts that if you mount to the handlebars one, you are gonna throw off your balance and two, you're gonna' get half of your video full of your fairing.
Pick up an "UltraPod" folding tripod. Get the full-sized one, ebay has them often, if not, your local Wolf camera or similar camera shop has them for under $20. Neat thing about them is fully extended they are about 10 inches high, have a fully adjustable pan and tilt head that is screw-lockable, you can extend one, two or three "legs", and it has a looped velcro strap. Here's where it gets cool...the legs are "v-shaped" so you can velcro it onto anything with a right-angle.
here's an example of the mini, but I suggest getting the full sized:
What I've done in the past is velcro it down to the chrome luggage rack on the top case and film BACKWARDS as I ride...or set it up on the rider in front of me, so I get film of my riding and the scenery...I did this on Deal's Gap and identified a problem I didn't know I was having with entering curves too deep. You can also reach it out further and film forwards. OR, if you really want to, you can strap it onto your bars, too...or onto your passenger footpegs (I've done that), or the side bag handrails or...
my two cents...