I passed 70-640 (TS W2K8 AD) on Firday with 897.
The breakdown of topics seems to tie up well with the percentages in the skills measured in the exam guide (
http://www.microsoft.com/learning/en/us/exams/70-640.aspx). A large number of the questions required no specific W2K8 knowledge, so those familiar with W2K/2K3 have a good headstart.
I used the official Microsoft press book, but wasn't impressed, probably as it was covering what was for me a lot of old ground. What I found more useful was a Microsoft document I downloaded which focussed on what is new to W2K8 (Changes_in_Functionality_from_Windows_Server_2003_with_SP1_to_Windows_Server_2008.doc). This was very useful in the areas where I was already strong (most stuff excluding that rebranded as AD (Certs, etc)).
I'll be busy on other things till December, by which time the Exam Cram for 642 should be available, so I'll probably use that next, along with the doc above.
Gordon
