There's an app for that! Well, actually, I've no idea if there's an app for that, but there are helpful scripts on websites.
Random Name Generator based on US census data; allows you to hedge towards "common" or "obscure" names.
Random Identity Generator creates one at a time, complete with birthday, address, occupation, height & weight, and other random-ish details.
Fantasy name generator for people who don't want modern realistic names.
Many many
other random generators: Medieval Name Generator, Magician Generator, Fantasy Gown Generator, Cuss-O-Matic, more. Lots more.
And once you've got yourself a pack of names, you can head over to
They Fight Crime to give them a plot.