I've BTDT - my first was a c-section for breech presentation and we knew about it from 30 weeks on. My advice: get proactive NOW, but don't worry about it. At 33-34 weeks your baby has roughly a 50% chance of flipping vertex on his own. You can do some things to encourage this. My advice would be to:
1. Get a recomendation on a practitioner who does accupuncture and moxibustion. This is actually the ONLY method that has a randomized controlled trial showing that it is significantly better than doing nothing. It works by encouraging movement of your baby - they *want* to be head down, but sometimes they get stuck.
2. Chiropractic - get a recommendation for someone who does Webster Technique. I would contact your MW or your local ICAN group. They probably know who is good for this.
3. Hypnobabies has a CD called "Turn your Breech Baby NOW" - it's a guided visualization. Might work, certainly can't hurt. Really any visualization and talking to your baby will help. This just may help you get there.
4. Snorkeling. Seriously, I'm pretty sure this is how my baby #2 flipped from vertex to breech (eek!) at 30 weeks. (fortunately, she flipped back). I was in Florida floating face-down in the water for around an hour and I think she didn't know which way was up. Maybe just try it in a swimming pool. Others have suggested swimming, surface diving etc, but I think being relaxed is key.
5. Combine all of the above. Especially the relaxation/visualization can be combined with other things. My second baby was breech at 30 weeks. I had 2 moxa treatments and was laying in bed early in the morning when my 2-year old son came to wake me up. He patted my belly, told me he loved me, and *bloop* I felt my baby flip around. Seriously, I couldn't believe it! You never know what will work for you.
If your baby doesn't flip by 37 weeks do a version (ECV). They work about 60% of the time and are very low risk. You may want to see whether there are any providers that will do a vaginal breech delivery in your area, too. ICAN again may be helpful for this. With any luck you won't need it, but you would likely need to have a consultation ASAP to establish care, should you end up breech at term and wish to deliver vaginally. If you are still breech at term and decide that a c-section is the best option there are many resources available to help you have the best experience possible.
Best of luck!!