You probably heard about the new Windows Shell, which will make its debut as the main command-line interface for Exchange Server 2007. This new shell just got renamed to PowerShell. It was originally known by the codename "monad" and was also called the "Microsoft Shell" or "msh".
This has been available as a public beta for some time now and it now reaches the Release Candidate 1 milestone. Download the RC and the documentation from http://go.microsoft.com/fwlink/?linkid=64772.