via pdroms

iLocation is a native program that pin points your current physical location and displays it in the iPhone's Maps application. It uses the location of cellular towers your phone is connected to estimate your location. It works exactly like Google's Mobile Maps for other phones.

Release notes:

- Will not publically release this, sorry. Google's database of cellular tower locations is not publically available and they'll most likely ask me to stop distributing this. Until they release a public api, I'll keep this for myself.
http://iphone.rustyredwagon.com/