Visual Studio 3.5 Release 2008 is coming with an icing on the cake . The .net framework libraries souurce code is being released under Microsoft Reference License (MS-RL).
The release will include full visual studio integeration and will intially have 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).
Additioanl release in months ahead will have WCF, Workflow, and LINQ !Boy that is exciting , No more wondering what happens inside that sealed function and step right through ! Read more at ScotGu's Blog .