http://www.callhunter.com/
Could be a good tool if you are getting harassing phone calls. Can track down who the number belongs to. Exotic owners are sometimes harassed by people thinking they should not own their animals so thought this could be useful.
Of course these things are mostly used if you got debt collectors calling so have that rap but they can be a good tool. I personally am reluctant to answer a call from an unknown number for many reasons.
7:42 PM
http://tirs.us/ will give you the callerid info and often more information on most US phone numbers.
Say hi to Pua for me!
10:16 PM
Well they sure have a lot listed.
We've been getting scam calls from a Canadian number. They either say our car warranty is about to expire or say they are calling about our credit card. Seems in either case they are fishing for credit card numbers.