We've released a new article that talks about some of the improvements and changes to the Exchange Management Shell in Exchange 2010. Introduced in Exchange 2007, the Shell, which is based on Windows PowerShell, is the powerful command line interface that you can use to manage your Exchange organization. We made improvements to the underlying infrastructure in Exchange to give you more flexibility around how and where you use the Shell, and how you define your permissions model.
If you're new to Exchange, read the article to discover what the Exchange Management Shell is, and how to start using it. If you're a Shell veteran, you'll want to read up on Role Based Access control to find out how the Shell makes use of RBAC so you can fully customize the permissions you give out to your administrators and your users. Be sure to read the links provided in the article which take you to more in-depth details about each of the features discussed in the article.