I never took the classes, but I managed to get ahold of some cds. I listen to them during my afternoon nap and to go to sleep nearly every day, and have been doing so for about 6-8 weeks. Lately I am listening to "Come Out Baby" every afternoon, and also a birth visualization or anesthesia or deepening each night.
I listened to "Joyful Pregnancy" every day for a while too, and found it really improved my attitude about this pregnancy!
For the birth, I have "Birth Day Affirmations," "Easy First Stage" and the pushing track loaded on my ipod. I am planning on trying them when I know I'm in labor in hopes that it will help - especially to get through the first part of laboring at home before the hospital. My husband has listened to the tracks as well - they put him right to sleep - and he is fine with them playing in the background while laboring or having me wear earbuds, whatever works.
If I find them annoying, I will ditch them.
Even though it has been a big time commitment with the tracks every day, I do think they have taught me to relax myself and sleep better - skills I needed desperately in life anyway - and that will continue to pay off long after this baby is born!