I bought one of those 'key chain cams' a few months ago. There's a video of it attached to a guys 1/8 ebuggy during a race a couple of weeks back
[youtube]rpcj8Q0N7yQ[/youtube]
^ That's me in the white hat, marshalling.

You can see the camera and another video here:
http://tsanrc.blogspot.com/2010/12/fpvkey-chain-cam.html
The trick to getting good clear video is attaching it
very securely to the car. I usually attach it to the roof of a car with servo tape, followed by wrapping electrical tape (or similar) very tightly around the car and camera. The video in the second link was only attached to the wing of a D8, again with servo tape and wrapped with elec tape. (that view is best, because you can see the suspension doing it's thing.
If it's a camera like this:
you can zip tie it to the shock tower nice and tight. (although it might get knocked of/broken during a roll over)
I can't be bothered to set the time on mine either.

I have instructions on how to remove the time stamp from these particular cameras but haven't tried it yet. Because you mess with the firmware, it's possible to mess up the camera for good.