Here's a couple tips:
Do not invest in a micro camera if it's 900Mhz, only go with 2.4Ghz. Mine is one of the 900's and reception kind of sucks.
Use alot of vibration isolations stuff (RC plane Rx foam works real good). If you don't isolate it, the video will suck.
Run a seperate power supply for the cam. Tapping into the main battery on an electric without some real voodoo noise filters will make the video suck. Running off of the radio battery does the same, plus it doesn't have enough power. Use Li packs for the best power to weight ratio. Heavy batteries will make your vehicle handle like crap.
The cam I used in the SandboxBash vid was a micro DV cam that recorded to a compact flash card (not radio linked to a base station). The drawback to this was a frame rate of 15 instead of 30 and a frame size of 320x240 (about half of what TV's are).
Make sure that wherever you put the cam it's protected from damage (rollovers, wrecks, etc), but not close to electronics or the engine. Get some lexan sheet and some thin servo tape. Cut a piece big enough to cover the rim of the lens. Cut some real thin strips of servo tape and stick the lexan over the lense. This will provide some protection to the lense, while not obscuring or hindering the view.
And lastly, avoid driving "in the car". On jumps you will get disoriented. Watch my vids and you'll see.
Hope that helps, and good luck, it's alot of fun doing in car vids.