In something out of a conspiracy theory movie, Google is introducing latitude tracking through Google Latitude. This Google Maps tool will let the user track friends automatically, in real time. Currently capable of tracking using a laptop, WinMo Symbian 60, and a Blackberry, soon this will technology will cascade down to the iPhone and Android users (hopefully soon since these early adopters don't like to wait).

Google states on their Google Latitude support page as to what phones are supported,