EJB 3.0 is the full specification that includes session beans, BMP entity beans, CMP entity beans, message driven beans and the new
Java Persistence API. Because JPA wasn't split into a second document until midway through the specification lifecycle, most people still use the term "EJB 3" to refer to both the simplification changes (POJO session beans, dependency injection) and the new persistence API.
JPA refers exclusively to the new persistence portion of the EJB 3 specification.
Cheers,
Merrick