Debug .net source code through Visual Studio 2008

With the news of open source code for Visual Studio 2008 now available i was wondering how do you achieve this and i ran into this quite detailed article by Shawn here - http://blogs.msdn.com/sburke/archive/2008/01/16/configuring-visual-studio-to-debug-net-framework-source-code.aspx

As of date .net assemblies that are currently available as open source or for symbol/source loading where developers can actually step into VS .net source code are:-
Mscorlib.DLL
System.DLL
System.Data.DLL
System.Drawing.DLL
System.Web.DLL
System.Web.Extensions.DLL
System.Windows.Forms.DLL
System.XML.DLL
WPF (UIAutomation*.dll, System.Windows.DLL, System.Printing.DLL, System.Speech.DLL, WindowsBase.DLL, WindowsFormsIntegration.DLL, Presentation*.dll, some others)
Microsoft.VisualBasic.DLL

I believe more will follow! happy debugging... Regards - Dipesh