I found this on ExpertVillage.com (great site). This isn't quite how they do it in Thailand. Instead of laying on your side, they have you on your front, and they literally walk on top of your back. Having a 90 pound Thai woman walking on your back is 100 times more painful than it may seem, but it's still pretty damn good.
Thai Yoga Massage: Back Walk -- powered by ExpertVillage.com