I found this great blog post on At Your Cervix (written by a Labor & Delivery Nurse):
Getting in position -- making changes to shake, rattle and roll
"Up. Move. Lean forward. Lie on your far left or right side. Squat. Walk. Dance. Hands and knees. Modified lunges. Sway from side to side."
The author discusses the common issue of back labor, which most often is a result of a posterior or otherwise malpositioned baby. She explains how position changes during labor can help move the baby into a favorable position, make labor less uncomfortable for the mother, shorten the duration of labor, and even avoid a c-section.
"Why so many posterior babies? Simply put - we're a reclining society. We sit back in our recliners, couches, office chairs, dining room chairs, rocking chairs and more. Our babies get into these funky positions from us lying back...This is why it is so very important to get up and move in labor"
She also explains that even with an epidural position changes during labor are possible, and important.
Please read the post.
Here are some more resources for information about positions during labor:
I know I can post more than this. If you're interested in more information about positions during labor, please post a comment.