.net framework source code

Debugging Into the .NET Framework Source Code with Visual Studio 2008

http://www.microsoft.com/uk/msdn/screencasts/screencast/304/debugging-into-the-net-framework-source-code-with-visual-studio-2008.aspx

article about this:http://blogs.msdn.com/b/sburke/archive/2008/01/16/configuring-visual-studio-to-debug-net-framework-source-code.aspx

download url

http://referencesource.microsoft.com/netframework.aspx

HOW TO DO IT IN VS2010

http://www.cnblogs.com/zhuqil/archive/2010/07/26/debug-use-net-framework-4-0-source.html