Heather, I did hypnosis last summer -- in-person sessions with a hypnotherapist (who also was an RN and had a degree in social work), and the hypnosis portions were put on CDs for me, so I can continue to use them.
The hypnosis was great, but I think I was not entirely open to it under the circumstances. I was just too self-conscious working with someone else that way. But the non-hypnosis portions, I think, did me a lot of good! It brought about some permanent changes, but did not affect my weight issue -- though in fairness, that was 'way down my list, believe it or not.
Hypnosis seems to be a grey area -- not a black-and-white, you're-hypnotized-or-you're-not kind of thing. It also seems to be far less mysterious than we generally think. It's just a stage of consciousness along the continuum between sleeping and waking. Some people are much more suggestible in that state than others, but it's really not "weird" at all.
If you have identified the behaviors and thought patterns you want to change and you know something about the process of induction, you can probably create your own hypnosis CDs... perhaps even more effective than commercial ones, because they can be so completely personalized.
I haven't done it yet, but I intend to make some for myself. Instead of music, as the therapist used, I'll use ocean sounds, I think... and I have several induction "raps" in mind, a couple that I liked from the therapist, and some I've created for myself. I'll add the suggestions I want to make to myself, and then reverse the induction, and let the ocean sounds fade out slowly. I think that would help a lot... not only with weight loss, but also with getting to sleep at night!