I have used a HoytTech camera and it does a good job however it must be plugged into another camcorder such as a Handycam and can be very tedious.

http://www.hoyttech.com/

I now use the POV.1 and really like it. Its digital (records onto SD card), completely waterproof, has a wireless remote for start and stop, and a viewing screen so you can see what your recording...

http://www.heartlandbowhunter.com/ProductCart/pc/viewPrd.asp?idcategory=17&idproduct=17

You can see footage from the POV.1 used on our show regularly as a second camera angle