This morning they revealed Geosense for Windows.
Geosense is a Windows Sensor that provides the Location and Sensors platform in Windows 7 with accurate and reasonably ubiquitous positioning information without requiring or the assistance of GPS hardware, enabling more practical location-based applications and scenarios on Windows 7.
The release comes with an open call to action to download and develop location aware applications against it. Who’s going to be the first out the door with a desktop FourSquare client?!