Depends on your learning style - to me, classes ended up being unnecessary, but everyone's different. I really wanted to take one, but the time and money involved made me try other avenues first. Ultimately I was able to learn what I needed on my own.
First, for the medical information about birth, I read Pregnancy, Childbirth, and the Newborn by Simkin (sp?) et al. I'd definitely recommend it, whether you take a class or not.
Then, for birthing and relaxation information in addition to what's in the above, I read The Birth Partner by Simkin (again, sp?). I loved it and would recommend it for sure. Friends also suggested Husband-Coached Childbirth by Bradley, but I didn't get around to that one.
In addition to the books, over the course of a several months I watched a few hours' worth of youtube videos on breathing techniques, relaxation strategies, birthing ball positions and uses, etc. Some were helpful, some not; I don't remember any stand-outs, but there's a ton of options out there.
For DH, we watched one section of BabyCenter's online birthing class with info about the stages of labor, just so he'd know what the terms meant. He already knows how to help me if I'm in pain or upset, so he didn't need anything other than vocabulary.
Then, as far as labor practice goes, I have had plenty of aches and pains on which to try out our coping strategies. We didn't plan to practice ahead of time, but every time something hurts, I let DH help me. Now we both have a good mental inventory of what works and what doesn't, which we couldn't have learned in a class. We also have gotten good at rating my pain - DH can easily tell the difference between when he's able to distract me versus when I'm in another world.
PS: A newborn class (especially if you don't have newborn experience or family to help you) could be a good idea. A breastfeeding class can't hurt either if you are going to nurse. More "hands-on" training might be beneficial in those two areas - if I had concerns about nursing or infant care I definitely would look into those.