Microsoft Advanced Windows Debugging and Troubleshooting team disclosed the exam preparation information for 70-660 (71-660 while in beta).
You’ll find what you need to know at: http://blogs.msdn.com/ntdebugging/pages/exam-preparation-information-for-exam-71-660.aspx
Since there currently is no prep material, I’ll recommend some books that I think will help prepare those who might want to take this exam.
These books will give you the fundamentals of Windows internals.
For get a developer’s perspective on Windows internals reach out to Jeffrey Richter’s Windows via C/C++.
To get insight into debugging take a loot at John Robbin’s Debugging Applications for Microsoft .NET and Microsoft Windows :
I’ve read a few chapters from it – mostly the managed code debugging ones, but there’s a lot of information on native debugging.
Although I haven’t read Advanced Windows Debugging, is has been highly recommended, so I’ll list it here too.
That is a lot of stuff to read and study and it sure is not an exhaustive list. For just one exam! But what did you expected from an exam that caters:
"Candidates for this exam are typically in the upper echelon of the technical staff at their companies."
So get prepared and good luck!