I stumbled across this while viewing Netscape this morning; there’s a website dedicated to finding and providing information about cellular towers around you. Simply punch in an address and AntennaSearch will return information on all of the cellular towers and antennas within a four-mile radius. The entire data-set returned is mashed up with Google Maps and also provides details on the carrier registration of the tower as well as the height.
Here’s an actual sample below of the details for my search. You can see the carrier info, height and more. By the way: if there are any future proposed towers on record, they’ll show up too.