You bet! With the release of Visual Studio 2008 Microsoft will be making viewable the Source Code for a lot of the libraries in .NET 3.5. There will be two methods of viewing the source: a downloadable browsing format, or integrated into Visual Studio. When integrated developers will be able to actually step through the source to the .NET classes themselves, while debugging.
How cool would it be to take a look inside the System.Threading class?!?
This includes the Base Class Libraries (BCL), System.Data, Windows Forms, WPF, and ASP.NET. Great stuff!
One of the major reasons I came to Microsoft was the companies shift in thinking. Transparency towards its customer base and developers, starting with things like Channel 9 and most recently with things like this. Change is good, and I hope you feel excited about drilling into some of this code as I am. =)
If you haven't already checked out Visual Studio 2008 Beta 2, it is free download, comes with a go-live license, and is available as both a download and a vpc. More info and download links can be found here.