The Infrastructure Planning and Design team has released a couple of updated guides for Windows Server 2008 R2 and the new features availiable there. IPD Guides are the foundation for any successfull implementation of Windows Server 2008 R2. The specific guidens updated for R2 is: Active Directory Domain Services, Internet Information Services 7.5, File Services and Print Services.
The guides are availiable for dowload at http://www.microsoft.com/ipd