There's a lot of threads with good recommendations. I'll tell you what I used...Schaum's outlines Biology, Kaplan book (in store w/CD), Barron's (lot's of errors, watch out), the Topscore CD and the ADA sample test. I was taking organic at the time, so that helped for that section. Using those materials gave me 8 practice tests total and I had a really good idea of where I stood before I took the real deal. Take a sample test and only study what you don't know. Don't waste your time on sections you're good at. Take another test and study some more. Good luck! You'll get it down!