Ever hate having a missed call with a random number, and you wish you could find out who it is before you bother trying to call back (assuming there was no voice mail left)?

Does anyone know of a way to look up those phone numbers for free? Every time I try to look one up on whitepages.com it has a link to a site that charges $15 but says it has all the information you need... I'm cheap. Anyone know of a free way or work for a phone company and can look up a couple for me? =P