For the book, "Head First EJB", which was basically written on the SCBCD Certification will be published around at the end of this week...
For the Commercial Exam Simulations, u may want to try, simluations from the following company..
1. WhizLabs
2. SCBCD exam sim from INESystems
3. softSCBCD from softlearn-systems.com
That's all I know...
Maybe there are more in the market.....
As a reference, u may want to read
EJB Specification from Sun...
Co-author of SCMAD Exam Guide, Author of JMADPlus
SCJP1.2, CCNA, SCWCD1.4, SCBCD1.3, SCMAD1.0, SCJA1.0, SCJP6.0