"TileMill, the free and open-source design studio for creating beautiful web maps, is now available for download on Windows. With the latest release, the map-making tool is fully operational on the three leading operating systems: Windows, Mac, and Linux. With Windows still dominating the marketplace, this is a huge development that will open the door to many more users being able to use TileMill to make custom maps."

http://www.pbs.org/idealab/2012/01/tilemill-now-lets-you-design-maps-for-the-web-on-windows030.html