Impecable timing, dude!
I studied for probably about 25-30 hours for the 3 weeks before the test. I studied all the NSCA study materials: the book, cd's, etc. Honestly, I don't think they really helped a whole lot. The things that helped me the most:
Take your time - the test is as much about knowing how to take tests as knowing the material.
Think critically - the questions require you to think beyond just simple numbers and facts.
Take more than one practice test - this will help you a) get an idea of how the questions are worded and b) get an idea of your strengths and weaknesses.
Know how to perform lifts how they want you to know them.
Read up on the relationship between anatomy and training ("structure and function") - that would be Mike's functional anatomy series:
Part 1 - http://www.T-Nation.com/readTopic.do?id=918697
Part 2 - http://www.T-Nation.com/readTopic.do?id=920621
Know how to determine intensity: HR, RPE, etc., especially for special populations.
I would first take a practice exam and then go from there, that way you'll get the most out of your study time. Also, try to find someone in your area that has taken the test and see if they'll lend you the study materials - you can check for certified persons at the NSCA website.
Hope that helps and best of luck.