It is good - deep relaxation techniques - but I've managed to get similar stuff for free for my iPod. You're supposed to listen to it very frequently - it might grate after a while, so I didn't listen to it too often. I don't think it's the same as the proper, hypnotising techniques which you learn on a course, though.
I did a HypnoBirthing course and have been lent the Effective Birth Preparation CD, which I've been listening to for the past week or so. I actually prefer the Natal Hypnotherapy one to the one we were given on the course (which involves too much visualising rainbows for my liking) but can't tell you if it's any cop yet because still waiting for LO to make an appearance. I guess it can't hurt, though it's probably worth keeping an eye on ebay for a secondhand one