Seriously, I started with EJB in Action, followed by Enterprise Java Beans. During that time I did some coding to test things myself. Then I went for the specs, and read ejb-core and jpa specs, taking notes of my own. Then, I read bits of Pro EJB (for example, XML chapter, and query language chapter as it has nice examples).
1)Ejb3 in Action by Reza (gives you good background to start)
2)EJB3.0 from Orielly (have code examples to practice and test on Jboss)
3)Go through EJB3.0 CORE specs and JPA specs
4)May be can try MKZ notes (for final revision)
5)Some mock exams
Currently i am in step 2) and quite happy with this plan