It depends which exam you're insterested to take. The current SCBCD exam (CX-310-091) is about EJB 3.0 and JPA 1.0. EJB3 In Action is a great book to learn about these. Oracle has decided to split both EJB and JPA into two different certifications : CX-311-093 and CX-311-094. These are respectively about EJB3.1 and JPA2.0. They are in Beta phase and are already closed. I don't know when the new exams will be officially published.
According to my calculations, the new Oracle EJB and JPA certifications should be available in the middle of December this year.
They said the certifications will be able approximately 6 weeks after the closing of the beta exams.
I am not affiliated with Oracle in any way and of course I cannot promise anything.