I passed 70-640 last week. that was a very tough exam.


there were a lot of questions on DNS and ADCS, some ADFS and ADRMS.
below are the resources i've used.
IT FreeTraining Videos
70-640 Configuring Windows Server 2008 Active Directory (2nd Edition)
CBT Nuggets 70-640 Active Directory w/ R2 Updates
Microsoft Windows Server 2008 - Active Directory Resource Kit (i've read the Part I only, since this book is not updated for R2)
Technet Library
I'm a completely newbie on this AD technology, what helped me a lot was the Part I on Active Directory Resource Kit book which lays out a complete overview of AD DS on it's physical and logical parts.