Navizon is a clever app. It uses a combination of GSM Cell data, wireless access points and GPS data to locate handsets. A handset equipped with Navizon and GPS becomes a data collection device which collects and records geo-tagged records of all GSM and WiFi sources it sees, then uploads the data back to Navizon when connected to the internet.It would appear that the iPhone variant of Navizon only operates in ‘where am I’ mode and not in ‘data collection’ mode - for the latter you will need either a Symbian S60 handset (such as the Nokia N95) or a Windows Smartmobile handset - both preferably with GPS.