Via Kurt, I learned about openBmap.org, a free and open map of wireless communicating objects.
From the website: "openBmap is a free and open map of wireless communicating objects (e.g. cellular antenna, Wi-Fi, Bluetooth). It provides tools to mutualize data, create and access this map.
Help us build a free database! Open source logging applications are available for Android2 phones, WindowsPhone6 and the openmoko freerunner freesmartphone.org phones."
The database currently contains for cellular objects: "169 countries, 578 mobile networks, 34,961 location area codes, 706,606 cells (which 218,727 are trusted)"