I just wanted to remind you that according to the post in the 10th of August in Mike Stall’s blog, the MDbg that worked on Beta 2 is also intended for use in the RTM release of .NET Framework 2.0.

You can get it from here.
It includes FULL source code for the debugger (which is a pure C# application) as well as additional samples and an extensions API (if you wrote an interesting extension please let me know).

I talked a bit about MDbg in a previous post.