I used to use a camera for a short time, but found that an external cam does a much better job and much more versatility. At chasecam, they sell very good ones. They just came out with a very high rez model. I love it.
http://www.chasecam.com/bulletcam.htm
These external cams just plug into many of your existing cameras. You can then put your camera in your glove box and all you'll have is a single wire that runs to the little lens. You just need to make sure your camera will take an external video feed, many do (even older ones).
I bought a tiny miniDV Canon video cam. I put it in the center console of my SRT. There is also a power plug there. It couldn't be more perfect. All I do is hit record on the camera and close the consol. I've gotten a lot of people in our club hooked on them, they're great.
Obviously cameras are very heavy, this causes them to shake (and also limits where you can mount them). The little bullet cam I use can be mounted anywhere. I even mount it outside of my car behind my wheels to get some unbelievable shots! I've also put them aimed in my wheel well when I was trying to diagnose some tire rub issues... Under the car... Very cool.
If you want to see the quality of the video, follow this link to the IL club's website. Click on the “racing” video. In there you’ll see lots of footage from the bullet cam. I highly recommend them. Just read your manual to be sure your cam will take an external analog video feed via RCA cable.
http://www.illinoisvipers.com/videos/index.html