I did the following:
Went through Head first Servlets and JSP a couple of times, nice explanations for newbies. Probably not so much for experienced developers
Studied OCEWCD Study Companion by Charles Lyons. Okay book, sometimes it feels like youre just reading the javadoc for the classes but nevertheless it helped me to pass so...
Ethuware tests! I must hand it to these guys, great tests. I felt comfortable on a lot of questions on the exam because i saw something similar in the practice tests. Highly recommended