If you are interested in coding for the .NET Framework and don't already know about Lutz Roeders' .NET Reflector then you should.
http://www.aisto.com/roeder/dotnet/
This superb utility lets you examine almost all of the .NET Framework in the language of your choice, VB.NET, C# Delphi etc. and see how Microsoft has coded it. You can also look inside the B4PPC dlls and other .NET exes to see how they are built and what they do. Download it and in case it is not obvious press the spacebar or invoke Tools -> Disassemble to see the code for the selected assembly. There are various add-ons, of variable quality, available via a link on the download page. I like FileGenerator which will produce a VS 2005 project file set, although actually getting it to compile without errors may be a battle!