Diving into geolocation
Speaking of the open web, here's Mark Pilgrim's take on HTML5 geolocation:
Geolocation is the art of figuring out where you are in the world and (optionally) sharing that information with people you trust. There are many ways to figure out where you are — your IP address, your wireless network connection, which cell tower your phone is talking to, or dedicated GPS hardware that receives latitude and longitude information from satellites in the sky.
You can also pick your location, or any other location at all that suits your needs, from a map using René-Luc's Firefox Geolocater.