http://www.microsoft.com/SLPS/visualstudiousers.aspx
http://www.microsoft.com/slps/
expensive！
.net framework sourcecode
http://weblogs.asp.net/scottgu/archive/2008/01/16/net-framework-library-source-code-now-available.aspx
http://blogs.msdn.com/sburke/archive/2008/01/16/configuring-visual-studio-to-debug-net-framework-source-code.aspx
http://www.codeproject.com/KB/dotnet/netmassdownloader.aspx