Beleaf in Fatherhood - (video below) From a father and for father's, but I believe great advice for any non birthing parent on how and what to BE for your birthing partner's birth.
A favorite book of mine for partners to read during pregnancy is The Birth Partner. It's an easy read straight through, or one may jump around and read what he or she feels most important. Many of my clients have read this together or separately, and it has never gotten a bad review. You will feel more prepared for the mystery of labor and birth and what your role is after reading this book!