TechNet has a level 300 webcast called "Installing, Configuring, and Managing Server Roles in Windows Server 2008" that you can download from http://msevents.microsoft.com/cui/WebCastEventDetails.aspx?EventID=1032294712&EventCategory=5&culture=en-US&CountryCode=US (registration required).
If you have access to the Windows Server 2008 beta on Microsoft Connect (https://connect.microsoft.com/), you can download the following items:
Microsoft Windows Server 2008 Server Manager Lab Companion
Microsoft Windows Server 2008 Initial Configuration Tasks Step-By-Step Guide
Live Meeting on Server Manager
If you don’t have access to beta builds of Windows Server 2008, you can still test drive Server Manager online using the Microsoft Windows ...