NPA.RMLABS.NET - Phone Number Geolocator

TRACK THAT PHONE NUMBER
Here's an interesting spin on telephone number lookups. Okay, so you tried finding their address using Google or some other reverse number lookup and you can't find it. Well, knowing the area code and the exchange can help you narrow down the location if you use the Geolocator. We tried this and it works pretty well - with one important caveat: the area codes appear to be out of date. We had to use Mobile's old area code (334) for this to work.
(Suggested by Lifehacker)