It is all 12v stuff, here is the main hardware list. The rest of it is just standard parts.
the side screens are just hooked straight to the cameras mounted on the sides and don't interact with the computer. The rear view mirror is paired with my phone and auto connects to it when in range. The computer is also paired to my phone and can use it to autoconnect to the internet when needed to update the radar images and gas prices list. The wifi connects to my home network and using the offline files feature in windows xp it syncs up my mp3s from the house so I don't have to even think about loading music in the car, it just does it automatically when I get back home before shutting down. The power supply sends the turn on and hibernate power button presses to the motherboard so I don't have to turn the computer on or shut it down. It turns on 5 seconds after getting ignition power and shuts off 30 seconds after I turn the key off. 15 second boot up time so by the time I am going it should be up and running.
I am running roadrunner as the front end instead of the windows shell. It does pretty much everything I need to control while driving. It can embed other applications inside itself so it can control megatune and whatever gps mapping program I want to run. I am running the lsx void 3.3 skin on roadrunner, it looks good and has lots of nice features.
MP3Car.com - View Video Post - Lsx Void 3.0 has videos of lsx running. Also check out mp3car.com's forums for way more information on what is possible with a car pc. It is even possible to do generic I/O from the computer so when I put the electric drive on my car I will probably use it to control the logic for the drive.