I've been gradually studying for the Exam for 6 months. Started with watching and taking notes for all the PrepCast videos. I followed along in the PMBOK. The practice exams the Prepcast folks put together were really essential to me passing. I did the first 3 and scored about 82% on each of them. I found the real exam to be easy in comparison. I wouldn't waste much time memorizing all the different earned value formulas, my actual exam had literally 3 questions where I had to do math.