Hi there! I've used hypnosis for my last three births and have taught to different hypnosis methods (HypnoBirthing and now Hypnobabies). There are three main aspects to success using hypnosis:
1) Releasing fears about birth. With HypnoBirthing this is done as a script in class. Hypnobabies students get a recording so that they can listen to a fear release as often as they want to or need to. It's really great to listen to in early labor as well.
2) Reprogramming your beliefs about birth. We are taught from a very young age that birth is dangerous, scary, excruciatingly painful, etc. Hypnotic childbirth scripts and recordings give suggestions for fast, easy, comfortable birth. While a positive attitude regarding birth certainly is something you need, you also need to take care of your innermost beliefs, which are housed in the subconscious. If those inner beliefs still hold on to "yeah, but birth hurts really bad" then that's how it will be experienced. In order to experience a comfortable birth you have to believe, at your core, that it's a real possibility. Daily practice is essential so that your mind is constantly getting reinforcement for the new beliefs regarding fast, easy, comfortable birth. The mind is lazy and will revert back to its old way of thinking if we don't constantly feed it positive food for thought.

Once you start your hypnotic childbirth studies you will find the most success if you commit to practicing every day until the baby is born.

3) Deep physical relaxation. The first two items take care of the mental aspects, for the most part. For the physical, you need to know how to deeply relax instantly, especially all around your uterus. HypnoBirthing leaves it at that--relaxation. Hypnobabies goes further and teaches you how to create and direct your body's natural anesthesia (endorphins) with very powerful hypno-anesthesia techniques. Hypnobabies also teaches Eyes Open Childbirth Hypnosis, which allows Hypnobabies moms to be much more active while staying comfortable and relaxed. Movement helps the baby rotate and descend into the pelvis and helps you to dilate more evenly and quickly. Again, daily practice is essential for maximal benefit so that you really
know what your body feels like when it is totally relaxed and comfortable and you can reach that deep relaxation instantly.
I have four kids so I know it can be difficult to find the time to practice. I also knew that my baby was coming whether or not I did and I wanted to be prepared.

The practice is simple and very enjoyable. I found that I could get the older ones occupied with an activity or movie and then practice during my younger one's nap time or I would wait until my husband got home from work. During my last pregnancy my then-2-yo enjoyed listening with me (and would fall asleep).
I personally recommend Hypnobabies over HypnoBirthing if you're looking for the most comfortable drug-free birth possible. Hypnobabies is taught as a
live class (scroll down to your state) or you can order a complete
Hypnobabies home study course. Hypnobabies was created by a former Bradley instructor of 10 years so I'm sure some of the great elements found in a Bradley class are in there.

HypnoBirthing is not set up to study alone at home and is only taught as a live class.
Here are over 100 birth stories of moms using hypnosis:
http://www.pregnancybirthandbabies.c...th_stories.htm
ETA: There other books out there such as
Mind Over Labor by Carl Jones. His book is helpful if you want to know how to write your own scripts and he gives a variety of techniques. After you write your scripts you could have your partner record them so you can listen to them or have him read to you every day (if he's willing).