lets say you know EJB2/EJB3 well enough to use but were looking for certification-prep material.
Mikalai Zaikin's
study guide, is a summary of the EJB/JPA specification, organized by topics. I didn't use it, but I think that's the kind of material you are looking for.
Then I'd say to go straight to an exam simulator like Enthuware's. These tools ask you the kind of questions you'll face at the exam. None of the books I've read have been good enough for that. I think that books like EJB3 In Action, Pro
EJB 3:
Java Persistence API are very good, but, although they contain most of the information needed, they are not aimed specifically at the SCBCD exam. In my case, Enthuware's mock simulator filled the gaps.