I use a Kodak Playsport waterproof camcorder mounted on a Pedco UltraClamp handlebar mount. I always record in the lowest resolution setting (848x480), but the picture quality is still very good. The camera was only $117 at Best Buy. I like the Pedco mount because it is quick-release and very adjustable. I can swap it between multiple bikes in seconds.

Here's my YouTube channel. It's all cycling-related videos. Some were recorded with a regular digital camera in my hand, but all the videos of me riding up and down hills were recorded with a handlebar mount and the Playsport. The first two climbing videos, recorded in February, were recorded with a Casio EX-S12 digital camera on the Pedco mount.