None at all! This is a free service from the folks at Unwired Labs .

Yes. We've included the source code of the script here . It's still in BETA though so if your platform isn't listed, we'd recommend a manual installation .

How does this work again? Each hour, our script asks your device to search for nearby WiFi networks and tell our service about it. We then use a WiFi positioning service that knows the physical location of these networks to locate your device.

How accurate are these locations? Typically between 10 and 30 meters. This varies depending on the number of WiFi networks the device is able to send & also the quality of information we have in that area.