OK, now that the iPhone has GPS this probably doesn't matter near as much, but I wondered how the iPhone uses WiFi to find your location? Does if just use AT&T hotstpots, does it use other public hotsptos, and is there any way to add wireless locations(like your own if you wanted) to this? The GPS is awesome, but i would like my iPhone to know when I am home, even inside where GPS gets no signal, and if it uses the cell towers it puts me several miles off.