http://blogs.technet.com/b/seanearp/archive/2007/10/03/net-goes-open-source.aspxWell, not open source per se, but courtesy of Scott Guthrie's Blog : One of the things my team has been working to enable has been the ability for .NET developers to download and browse the source code of the .NET Framework libraries, and to easily enableen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)