The evangelists at Microsoft Across America have just released a great 8-part screencast of Windows Server 2008 Core.  None of the videos are longer than eight minutes and most are around five so WATCH THEM ALL!  Here is an excerpt from Keith Combs's article,

"At its "Core", the Windows Server 2008 Core installation option is a customer requested version of Windows Server.  You told us you wanted to build headless servers.  You told us to get rid of the fluff and just give you a server you could administer remotely or with scripts.  You told us to reduce the attack surface and only run what was needed.  You also told us that you wanted to create special purpose servers. 

You asked, we delivered.

Windows Server 2008 Core allows you to install the Active Directory Domain Services (AD DS), Active Directory Lightweight Directory Services (AD LDS), DHCP Server, DNS Server, File Service, Print Services, Streaming Media Services and Web Server (IIS) roles.  There are also a number of features you can install."

With that said...I'm going home.  Good Luck and Good Night.