Bill:
The book is written for a developer with either
EJB 2 or a Spring/Hibernate background to jump right in (like all other "In Action" books). Unfortuntealy, we do not have a "EJB 3 for the Spring/Hibernate" developer chapter/section specifically. In general, such material would probably be inflamatory. However, we can consider writing an article on it if there is interest.
Reza