Fitness Mentors helped me pass the NASM exam.
The official NASM prep course left me woefully unprepared, and I'm so glad someone pointed me to Fitness Mentors before I signed up for the test. I don't think I would have passed without it. My only complaint is that the training material had a few factual inaccuracies. However, the topics were covered so thoroughly that the mistakes were easy to catch. Finally, I'd recommend you get a paper copy of the NASM book to read along with the audio lessons. The text will match the lesson better, and you'll be able to highlight and make notes as you go. Good luck!