Try the12volt.com, it's got all sorts of info about car audio and electrical.
They have wiring diagrams and calculators designed to help you do it all yourself. The even have wiring diagrams for lots of different vehicles. Check it out.
Check this thread to see some really affordable dash leds upgrades. Easy, cheap and look great:
http://67-72chevytrucks.com/vboard/s...d.php?t=636315
http://www.the12volt.com/