I highly recommend hypnobirthing. I've also heard great things about the Bradley classes and I had a Bradley book that i thought was very helpful explaining the different phases of labor. Also a good book for your labor coach - Bradley is a good class for couples who really want to share the experience, I think.
But to me the biggest thing you can do if you really want an unmedicated childbirth is to choose a midwife practice instead of an OB. For my first pregnancy I had an OB and as it turned out, no pain relief but that was because things progressed really quickly. I definitely felt like there was "a system" that everyone falls into with that type of birht. Although everyone was very nice!
My second childbirth, we had moved and I went to a midwife practice, hypnobirth coach, and I delivered in the birthing room at West Suburban (in the tub.) It was really nice, but the nicest thing to me was that although the midwives can provide all the same services if you want them, there's not that assumption that you want the epidural if you say it hurts, you know?
Best wishes! I think the most important thing, of course, is healthy baby/healthy mom. But if you can do it, it was a really wonderful birth experience.
ps, I also meant to mention that the hospital birthing class (northwestern) I took was nice enough, but not helpful for natural childbirth. Sure, we did some lamaze breathing and watched a video, but I would not say it was a true birthing class to prepare you for natural childbirth.