I just got an iPhone 3GS. I noticed that wherever I go in the city (downtown Vancouver) my iPhone GPS on Google maps shows a huge bubble of where I might be, and the blue dot in the center is usually very off. However, if I turn on Wifi (and do not connect to any networks... in fact, I've never once associated with any wifi network since owning the device) the GPS location in google maps becomes just the exact blue dot, and is very accurate. How does having wifi on help it locate me? For example, I turn on the iPhone's wifi in my condo, and GPS gives an exact fix of where I am... but the iPhone isn't connected to any wifi networks, and the phone can only see 3 SSID's of some random wifi routers of neighbors in my building?? What gives? I don't want to leave wifi on all the time just so I can use GPS... it is an unnecessary drain on my battery since I don't use wifi ever.