I listened to the PM Prepcast, read an outdated Rita mcCulskey guide and did all the practice questions (then doubled back and studied the areas I missed questions on), and I took the free practice sim at headfirstlabs and found their critical path exercises to be very helpful (and free).. but the thing that helped most of all was my experience and the ability to take the things unlearned from the above references and use them or imagine how I would have used them on the job. I took about a month to study and put in 30 hours of study time in the days before the exam.