I recently passed Exam 70-461. I used the Exam Training Kit from Microsoft Press. I was able to order the book earlier this year... March or April time frame. It's by Itzik Ben-Gan, Dejan Sarka and Ron Talmage. I think it goes a fairly good job of covering the material on the exam. I also bought a developer edition of SQL Server, so I could install it at home and try out the new language features, etc.

For Microsoft certification exams in general, I tend to take the practice tests in certification mode to see if I'm ready. If I can get 100% on several practice exams in a row, then I feel I'm in good shape for the exam. That said... The exam questions are always more difficult, then the practice questions.