We've had some problems where I live with car drivers who drive too closely to cyclists, so I decided to video my daily bike ride to work each day. Long story short, it made more sense to use a head-mounted camera than to attach one to the bike. (Vibration, view angle, etc)
Fortunately I already owned a micro-camera, the only challenge was to find a way to mount it - and you can see the solution in the photo above.
Step 1: Materials
* Micro video camera ($13)
* Head-mounted lamp ($3)
These Micro DV cameras range in price from maybe $90 to $13 shipped. It may depend on whether they're being sold in a spy store or as a toy for children :-)
The head-mounted lamps are all over the place now. Mine was a cheap one from China which was already broken, so I didn't mind dumping the flashlight to free up the headband).
Step 2: Prepare the Head Mount
Take the head-mounted lamp and remove the flasdhlight from the mount by removing the one screw.
Step 3: Prepare the Camera
Step 4: Attach the Camera
Hold the head band with the mount facing away from you, and the camera in place on the other side of the mount where it is going to end up.
Take the right hand side of the rubber band, pass it round the back of the headband, and then round the front of the mount again on the left.
Do the same for the other end of the rubber band that's on the left: take it around the back, across to the right hand side, and hook it round the front again.
If it all worked out right, it should look like the final image in the series above.
Step 5: Use It!
Your head makes for a pretty good shock-absorber - your movie should be fairly stable, except when you're looking to the left or right at junctions. Good luck, and I hope you never need to use the film from your 'accident cam', but if you do find yourself in an altercation with a motorist, the record should come in handy for the insurance and the police.