One of the last bastions of secrecy has just fallen -- people who use cell phones, those smug jerks (I use one, too, so don't get offended -- I'm just like you) think that they're all high and mighty because their numbers aren't listed and you can't tell who called you if you don't recognize the number.
Well, get down off your high horse, all you people (and me) because reversemobilephones.ogr has a Reverse Mobile Phone Lookup that actually works. I know it works because I tested it on The Boy's prepaid cell phone and looked him up and it got him - -he's on there, even though his phone is (a) new and (b) prepaid and (c) hardly used and (d) often left underneath his shoes in the back hall, where I constantly trip over it and have to yell at him to quit watching ESPN and get up here and pick up his @(#*$&! shoes!
That last one makes it especially hard to look up. So if you want to or need to find out who's' using a cell phone to call you -- or who's leaving their cell phone in the back hall -- use reversemobilephones.org.