Meg,
I used the PMI-ACP Exam Prep by Mike Griffiths (ISBN 978-1-932735-98-7) to study. I read the book cover to cover and took the end of chapter quizzes. Then, of course, I used the PMI-ACP PrepCast. Finally, I found a few online PMI-ACP free exam's, however I found them not as near to the actual exam. But, don't discount them, it is a matter of material reinforcement.
On my exam, the questions were straight forward. It is the answers that will get you because they are similar. One thing that really does help is knowing how to take this exam. For example, marking out obviously wrong answers so if you have to guess at it, you at least have a 50% chance. By the way, when I guess I usually pick B... statistically a better choice based on odds
Matt