The Microsoft Learning Exchange Server 2007 Page is now live at:
As the page says:
During the beta release, Microsoft Learning is offering two free e-learning courses that will show you how to take advantage of innovations in Exchange Server 2007, including Unified Messaging and new security and disaster recovery features.
The courses available now are:
Clinic 3053: What's New in Microsoft Exchange Server 2007 Administration
This clinic introduces the new role based installation procedure for Exchange Server 2007 and describes the various server roles. It also provides guidance on how to administer Exchange Server 2007 by using Exchange System Manager and Exchange Management Shell, in addition to introducing key concepts that are related to Unified Messaging.
Clinic 3054: Overview of Microsoft Exchange Server 2007 Architecture
This clinic describes the most significant changes that are in the Microsoft Exchange Server 2007 architecture, including the communication between the five server roles and changes to the message store. It also describes different deployment scenarios.