Remember to sign up for Exchange 2007 Beta2!
The Exchange 2007 Beta2 program is going to be a Public Beta. Everyone who signs up will be accepted into the program and given access to the media, so if you have any interest at all in Exchange 2007 and the changes that will be coming, make sure that you remember to sign up. Indications are that Beta2 will be available at the end of July.
In addition, you can now find all the most up-to-date technical documentation for Exchange 2007 online, and there are also other great resources such as sample Monad (PowerShell) scripts.