Microsoft Releases Source Code on SourceForge:
"On Monday, Microsoft released some of its code under an open-source license, and posted it on SourceForge, the open-source code repository.

To date, Microsoft has made its source code available under a variety of licensing mechanisms, all under its 'shared source' umbrella. But until today, the company had not released code under what is commonly considered a true open-source license."

Microsoft made available an internally-developed product called the "Windows Installer XML" (WiX) to SourceForge. The code is downloadable here.

WiX is a toolset for building Windows installation packages from XML source code. It runs on Windows NT and Windows 2000.…

http://sourceforge.net/projects/wix/

http://www.microsoft-watch.com/article2/0,1995,1561953,00.asp