Well, I suppose there isn't a *way* to prepare for the exam. Personally I purchased 'Head First EJB', which is written by two of the authors of the SCBCD exam: Kathy Sierra (who is also the person who started this site, and who manages it) and Bert Bates. I bought the book because the critic on internet was good, and I have to admit that, apart from the initial mistake on the first exercise and the responsibilities and exceptions (which I would have put earlier in the book, while these are nearly towards the end), the book is great, Kathy masters the 'learning environment' and she knows how to teach people, but what I really (or O'reilly ) like of this book is that is filled with sense of humor, different 'teaching styles' for different 'learning styles' and for the first time since I read technical book, a book that is supposed to teach people who don't know is actually written as the readers would be 3 years old kids (which absolutely the right thing to do).
You are free to choose your own reference; personally, I use the following learning style:
1) Give each topic a first, quick read to see if I am gonna die or not; 2) Read and repeat (loudly) the most important concepts. I learnt with SCJP that repeating loudly fixed concepts in my mind more firmly and also that many things that I supposed to know, actually were really different. The reason? To repeat you *need* to understand, and understanding is the key. As Morpheus said in the Matrix I: '...There is a difference between knowing the path and walking the path' and personally I find that reading and repeating helps me in 'walking' the path. 3) Assess my knowledge. This is very, very important. Assessment is a must in the learning cycle; at the end we must remember (also this was in the Matrix - reloaded this time -...still Morpheus) that we're going to take an exam with 70 questions, around specific topics, and assessing our knowledge against those topics is crucial; 4) Try different mock exams (buying some if necessary), because different points of view give you different level of difficulty and different questions. If you answer correctly to the same topic presented in 4-5 different ways, you will answer correctly also to the exam question.
5) Depending if you are religious...Pray, pray a lot.