Originally Posted by SCSInet
Those low profile fans are not generally available as computer fans... you need to look at an electronics site.
Start here:
jameco (dot com) *best bet*
mcmelectronics (dot com)
partsexpress (dot com)
digikey (dot com)
Try also to find one with a current rating that is close to what you have. If your fan is 12 volt at .30 amps (or 300 milliamps or ma), and you find a replacement that is the same size but pulls .80 amps (or 800 ma) it's a safe bet that it's going to be higher flow and therefore much louder than the one you have. It doesn't have to be identical, but if the one you choose is way off, it's probably either too loud or too quiet (and therefore doesn't move enough air to do the job).
What he said, they may also rate the flow with cfm. Cubic feet per minute. I think if I remember right. That may help you choose too.