About a months and a half ago Mozilla announced its Location Services. It is "an experimental pilot project to provide geolocation lookups based on publicly observable cell tower and WiFi access point information". In other words, it is going to provide a similar service as Google's location service that Firefox currently uses for its location aware browsing.
In order to provide this service, they need geolocated data so that they know where WiFi access points and cell towers are. They have released a tool, MozStumbler, that allows everybody to collect this data and provide it to Mozilla. I believe that there should be open alternatives for important services like this, and I think that Mozilla seems like a good caretaker of this data, respecting privacy. So I have installed MozStumbler and turn it on whenever I go on a new route through town.
The application isn't the prettiest as you can see, but it does work well. There is also a "Test Mozilla Location Services" which uses their API to lookup the location—without using the GPS. Ichnaea is the public API that you can use to do lookups yourself. The Geolocate API implements the same interface as the Google Maps Geolocation API endpoint. But there is a more extensive Search API as well. I will soon be upgrading Haunt to use this new API as the one it currently uses is discontinued.