I can second all of Guidos comments above - dont bother with the tank mounted option, go for the RF Concepts or Highview bullet cams - *very* good quality. Like VMan, I just havent got round to figuring out how to get into PC formats yet!!!!
and dont go for the bum bag thingy either - i got black flagged at Cadwell last year doing this. Most new-ish palm-held vidcams fit under the seat in just fine (make sure plenty of padding).
Theres going to be plenty of us there with cams, so I'm sure if asked nicely/bribed) you can borrow one for a session and avoid all that outlay.
[Edited on 27-4-2004 by JasonBoswell]