My nurse midwife didn't even worry about my son's positioning until late in the pregnancy, like around week 30, maybe even later. My son wasn't breech, but he was laying on his back, so that his head was on one side of me, and his feet on the other. My midwife told me to go to the Spinning Babies website and look at some of the stretches and exercises listed.
I did the "inversion" technique off of my futon (with my husband's help!). I never felt my baby move or any weird sensations, but when I went back to my midwife, she said it felt like my son had moved into position. A real quick ultrasound confirmed that he had!
http://spinningbabies.simplwebsite.com/techniques/activit...
One thing about babies getting into position early in the pregnancy is that they can float away into a different position, and not stay there.
I have also heard good things about chiropractic care and turning babies.