Sorry for my delayed answer
I prepared for the exam about 2-3 hours/day for 6 months.
As preparation materials I've used:
- K&B book
- Khalid Mughal book
- the online mocks listed on javaranch.com
- Whizlabs simulators for java 1.4 and 1.5
- Enthuware simulators for java 1.4
Tips:
- during you preparation for the exam, build a list with all the issues that you consider tricky and, very important, review them before the exam day
- bookmark the mock questions that you get wrong and, very important, review them before the exam day
- use notes (find the links to them on javaranch.com) and use the ones that you consider better organized especially for IO, String/StrigBuffer, Collections etc., and review them before the exam
- take 2 weeks before the exam and only take mocks and review your material (notes, chapter summaries in K&B book, etc.)
- take the mock exams in conditions as closely as possible as the real exam (nr. of questions, time allowed, etc.)
- during the exam, if you don't know the answer move to the next question and review the unanswered question at the end
All those above helped me to get the exam with a satisfactory score
I wish you success with you preparation / exam

[ November 25, 2008: Message edited by: Cristian Popescu ]