I just finished reading The Birth Book by William Sears, MD and Martha Sears, RN. The Searses are a married couple that have been working in obstetrics for many years, he as a physician and she as a labor & delivery nurse. They also have 8 children together (7 biological, 1 adopted) so they bring that experience into the fold as well.
If you are pregnant you should read this book. The goal of the book is to teach a woman how to have a safe and satisfying birth experience. Their personal belief is that natural, unmedicated birth is attainable and empowering, however they do not condone a woman for choosing to have pain relief or other medical interventions. They simply explain many basic procedures, weigh the benefits and downsides and leave the decision up to the reader.
What makes this book so unique is that Martha really, really knows what she's talking about. Throughout her 7 pregnancies and deliveries she has had a variety of birth experiences - from a medicated hospital birth to a soothing home birth surrounded by her family. She can honestly explain the difference between the births and give helpful advice. Not to mention the hundreds of births she has assisted as an L&D nurse.
Even if you have no interest in a natural childbirth this book is a wonderful reference. I believe the best way to prepare for your birth is to be educated and know what you want.