On Board camera's

[tristancliffe]

No, but I know people who have. It's a very, very expensive, standard definition camera with poor sound (although I think it is possible to use an external microphone). You can link it with an AiM data system to get an overlay on the video... but you can do that with Trackvision software (or Chasecam's Dashware, and there is a really cheap and horrid overlay program that I can't remember the name of).

Personally, I wouldn't bother unless you are made of money and aren't able to understand a good deal when you see one.