If you've just started to learn about the new server roles that are a part of the Microsoft Office Communciations Server 2007 release, a great post for you to see is over on the Communicator Team Blog by Rui Maximo.
Of course you can find lots of helpful documentation on Office Communications Server 2007 on our TechCenter page http://technet.microsoft.com/en-us/office/bb267356.aspx
OCS, Server, Microsoft, Office Communication Server, Web, Guide, Document
Source:? OCS Blog