I used Hypnobabies. I had researched both programs (hypnobabies and hypnobirthing) and found the home study version of hypnobabies to be much more complete and detailed. It is a 6 week program, which helped me to learn to focus all my energy. I can't say that I didn't feel any pain, however using the hypnobabies' techniques, I was able to relax and cope with pain in a much more controlled fashion.
I ended up with back labor, which, as you know, is quite painful. I had my midwife give me sterile water injections. That helped a lot. I also used a doula (as one poster suggested). I can't convey the importance of mommy-oriented support.
One thing I can tell you is that it is very important that you are open to the ideas behind hypnosis. If you are a skeptic, then it's probably not for you. However, if you feel that it is something that could work for you, then try it. If nothing else, it helps you to manage your pain.
I had people telling me that they had never attended a natural birth that was so ... uh, quiet and controlled. It will help you to focus. Just don't think of it as a pain-free fix. It's about pain management and teaching your body (& mind) an effective way to cope.
Do you know about the hypnobabies Yahoo! group? You might find it interesting, there is a lot of helpful and informative discussion. It's a great place to see what others are saying about the program.
http://health.groups.yahoo.com/group/Hypnobabies/
Truthfully, I still kind of use it whenever I hurt myself (burns, cuts, etc.).
Best of luck!