There is the website. http://www.hypnobirthing.com
The book, "Hypnobirthing, The Mongan Method", which comes with a CD which has relaxation techniques as well as what they call "birth rehearsal imagery".
Then, there is the Rainbow Relaxation CD which has 30 minutes of affirmations and 30 minutes of relaxation techniques. I listen to these online. http://www.archive.org/details/HypnoBirthing
You can also search youtube for videos of Hypnobirthing births.
I've been taking a class, but honestly, all of the resources out there are sufficient. I hate to say it, but I'm not getting anything from my class that I couldn't have gotten by properly using the resources I've already listed.
I'm glad that others are having better experiences with their classes. We're only half way through the course, so maybe it will get better.
Our teacher is a doula, and she's very sweet. She just seems to get off track a lot with personal side-notes, and we so far haven't done any actual practice or rehearsal of breathing, relaxation, or deepening techniques. It's been a lot of watching videos, talking about the book, and relaying personal thoughts, feelings, and philosophies.