The Stuttering Foundation has a wealth of information about stuttering for kids, teens, and adults who stutter as well as parents, teachers, and pediatricians.
Friends is the National Association for Young People who Stutter. Find a local conference and meet other kids who stutter and their families!
The National Stuttering Association is the largest support group for people who stutter. See their online resources as well as information about local support groups and the annual convention.