Hi Arpita,
As you said, there are two different versions of the SCBCD :
- Sun Certified Business Component Developer for the
Java Platform, Enterprise Edition 5 (CX-310-091)
- Sun Certified Business Component Developer for Java 2 Platform, Enterprise Edition 1.3 (CX-310-090)
The latest is Edition 5.
SCBCD1.3 is about EJB2.0, whereas SCBCD5 is about the brand new EJB3.0.
Head First EJB is aimed at SCBCD1.3, the old exam. There's no Head First books for version 5 yet. And I don't think there's any plan to release one soon.
With Scjp1.4, you can go for any of them.
EJB3 is a fairly new subject, and there are only few documentation on it. I don't think there are books aimed specifically at the exma yet (may be wrong).
EJB2 and EJB3 are two different beasts, so you may decide on which one to go for, depending on your requirements.
Good luck.