There aren't any books yet for the new requirements. I teach with the McGraw-Hill "Mike Meyers A+ All in One Exam Guide", which has the distinct advantage of being readable, not as dry as the other books on the subject.
Frankly, you and most of the other folk who visit here should be able to certify in A+ without ever picking up a book.
I'm trying to gauge enthusiasm for the MCDST cert as well. It looks nice and entry-level, covers common MS applications (Office, OE, IE) and really looks like it has useful criteria for certification. I think it would be a good class to teach. One of the shortfalls of A+ is that there's very little practical knowledge needed pass the test, and very, very little actual knowledge of Windows and Windows apps.