I used it for DD's birth, and while I never really feel that I was able to get fully into Hypnosis during her birth (because the pressure waves - aka, contractions - were right on top of each other) I feel that it really helped me to be confident in my body and my ability to birth my baby. Actually, it helped me to have that attitude all through my pregnancy...and into this one. DD's birth wasn't painful at all...intense, yes, but not painful. (the midwifes hand in my uterus to remove the retained placenta was quite another story!)
I've started listening to it again when I go to sleep and throughout the night and am finding that I'm sleeping better since I started listening again...it's so soothing that if I wake up, it lulls me right back to sleep. Once DH is out of school at the beginning of next month, I will start setting aside time to actually focus on the scripts and listen without the intention of falling asleep. I'm also going to practice going into hypnosis with my hand in a bowl of ice water, so that I'm practicing in a less-than-relaxing situation. Hopefully that will build my self-hypnosis skills so that I'm able to get there during the birth this time.
If you're using Hypnobbies or a simple program, have you started practicing yet? If you've used it in the past, what was your experience?