Here ya go;

[link to www.truepeoplesearch.com (secure)]

We use it all the time - pretty decent for free.


(If you're being spammed and trying to track them.)

Spoofing a number for telemarketing / debt collection / etc. is a Federal Offense.
Also, phone companies purchase blocks of numbers from the FCC to provide to their customers (it's why they'll incentivize you to bring your number with you, because they're basically stealing a competitors number who had to pay the FCC for it - they're expensive, and limited.).
So if you can figure out who legitimately owns that number, they have an FCC compliance department (or similarly named) - just notify them someone is stealing their numbers. They'll track it, notify the FCC, and you can see where it goes rom there.


Peace