This is super awesome!! We announced yesterday that we are going to make the . NET Framework libraries source code available as an online resource or download for everybody!!!
We'll begin by offering the source code (with source file comments included) for the .NET Base Class Libraries (System, System.IO, System.Collections, System.Configuration, System.Threading, System.Net, System.Security, System.Runtime, System.Text, etc), ASP.NET (System.Web), Windows Forms (System.Windows.Forms), ADO.NET (System.Data), XML (System.Xml), and WPF (System.Windows). We'll then be adding more libraries in the months ahead (including WCF, Workflow, and LINQ). The source code will be released under the Microsoft Reference License (MS-RL).