I got mine from Cabela's Automotive/ATV catalog. If you look on this page:
http://www.cabelas.com/cabelas/en/te...=category&rid=
I got the $49.99 unit. It has a compass, in/out temp, and displays your battery voltage. It is illuminated and runs off one of the 12V plugs on the dash. The only bad thing about it is the mounting options are limited -- you can really only mount it upright on a level surface. I have a prerunner, so that means I have 2 more cup holders in the console next to the shifter (no 4WD lever). I mounted it here with some adhesive velcro strips.
If I was buying one of these today, I would get the $129.99 compass on the page above. It has a lot of neat features, and it looks like you could mount it under the rear view mirror.
I ran the temp probe out the firewall, and mounted the sensor under the front bumper. I read somewhere that this is where most of the OEM sensors are located. It seems fairly accurate, within a few degrees. I'm judging by bank thermometers, which can be inaccurate, but it's always withing 2-3 degress of these.