Well, in light of the little alternator debacle of late I figured I'd post this up...

http://www.uneedapart.com/used-auto-parts-request.php

Basically it's a search engine for parts. My firend just used to to find a radiator for his Jeep.. within two hours he had 12 emails from difference places with their prices. Ended up getting a new one for $125, whereas teh best price he found himself was closer to 185.

Haven't used it myself yet, but I'll let ya know if I do... Just thought I'd share the link..