I posted a while back about our decision to turn our 3 year old BACK to the rear facing position in his carseat. After watching a video about the subject, I was compelled for his safety to have him rear facing once again because of his weight. He was a light pounder!!! Only 28 lbs at 3 years of age. The NEW recommendation in 2011 is to have your children rear facing at least until 2 years of age, but they recommend rear facing until they hit the maximun height and weight of a rear facing carseat (which is our case is 40 lbs rear facing). As long as the child's head is one inch below the back of the carseat, they can face the rear.
Please read the above article and read my posting below from last year. It has an eye opening video which will make you think twice!http://homegrownwithlove.blogspot.com/2010/07/i-found-this-very-interesting-i-went.html
........and then turn your little ones back to rear facing!!!