Cell (Phone) Location API
GNUCITIZEN beschreibt GEO-tracking Mobile Phones
The obvious way of tracking an already exploited phone is by means of GPS (Global Positioning System). Correct! However, given the fact that most mobile phones does not posses these feature, including the iPhone, we need to leave it for now and find something else that will give us to one degree or another a similar result. As you probably know, mobile phones are also known as cellulars, an old name (technology) which refers to circuit-switched voice telephone communication via cellular radio channels. Speaking generally, phones connect to cell phone towers. The density/availability of these towers affect the strength/availability of the signal your mobile phone gets. Keep in mind that I am very general here.
Ok, soweit nichts neues, aber dass man an die Infos über die aktuelle Zelle so ohne weiteres rankommt wusste ich nicht: Yahoo’s ZoneTag Cell Location API
The cell location web service allows you to access the ZoneTag Location Services and get the best known location for a given GSM cell tower ID.