There's a few ways to be hypnotized for a specific reason.
-Find a physician or psychcologist that practices hypnosis. Only one or two sessions with them would be necessary. They'll put you into a hypnotic state that will assist you in future self-hypnosis, allowing you to fall into a deep state easily by yourself. Do NOT go to some schmuck that advertises as a "hypnotist." This is said to be the easiest way, but I think its better to be patient and learn yourself.
-Learn to do it yourself. Buy a book on self-hypnosis and/or meditation or you could probably find info on the internet because its fairly simple. The difficult part is the practice. You should learn the different levels of the subconcious, then how to get to each. If you're experienced with meditation the first couple are easily achieved, and are usually adequate to induce hypnosis. All you're basically doing when trying this is learning to command or utilize your subconcious mind. You can test this after a couple weeks of practice. When you test it under a subconcious state, without moving, your subconcious will move your body to represent different things.
Basically, all that the tapes do is plant words and phrases relevant to your purpose. When doing it by yourself, you simply think these words repeatedly. Its better to do it in your own words anyway, because it would probably be hard to find a tape at Barnes and Nobles that tell you you are going to be a "fearless, emotionless, perfect killing machine"
I've taught a couple of people the basics of self-hypnosis, and I'm always happy with the results my students have. I've gotten calls from people I use to teach that have continued to practice, and have done amazing things with it. I personally have been able to have things such as fear or apprehension shut down upon the initiation of a confrontation. I have reacted to very high-speed situations completely flawlessly and without thought as though I was picking my nose, because that's how I trained my subconcious to react.
Any closed minded person that dismisses hypnosis as mystical bullshit is one of the people that will never reach the potential of their body or their training. I promise you that if you practice this religiously, you will be surprised by the initial results, and extremely happy by the future effects on your training.