Just thought I should add to the people who mentioned this before (Paul Gielens, Chris Sells and Lutz Roeder of course): .NET Reflector is now available in version 4.0, supporting the Longhorn and Whidbey releases. Boy, o boy, I will do some major reflection on ObjectSpaces again. I was totally sad when I found that the previous version of Reflector did not work with the PDC and CTP bits. Anakrino worked for the PDC bits, but not with the CTP build and is not as powerful as Reflector to begin with.
Oh, and do I agree with Paul: download it, learn to work with it!