A great document that should be used a lot: Exchange Management Shell Quick Reference for Exchange 2010.
This download contains a quick reference sheet that can be used to access frequently used Exchange Management Shell cmdlets and syntax in Microsoft Exchange Server 2010.
The Exchange Management Shell provides a powerful command-line interface for Microsoft Exchange Server 2010 that enables automation of administrative tasks. This quick reference guide provides a list of frequently used cmdlets, important conventions, and useful tips. The information is presented by feature area, such as recipient, transport, and database administration. This quick reference guide applies to Exchange 2010.