I love this idea. Good to know of a place close by, Happy Hooves. I found out about them through Living Socia'ls deal today. For $60 (50% off), you get three lessons.
After looking over their website, I am going to wait on the deal, but am surely going to keep this place in mind for when my daughter turns four. For $25 a lesson, she will get 30 minutes that are geared towards helping the young rider become comfortable around horses.