Hi, a few days ago I passed the exam with 85%.
During the preparetion i used
Head First Servlets and JSP,
SCWCD Exam Study Kit: Java Web Component Developer Certification, Specification for the
Servlets 3.0, enthuware tests, exam simulater form Piotr
http://exam.piotrnowicki.com/ , and tests from Nikos ( nikojava.wordpress.com/ )
Enthuware tests realy worth it, because couple of questions from the exam were the same as in the tests.