There is no reliable IQ testing yet that is done over the Internet that a school will accept. There are private educational testing centers that you can locate either through your local school district or in the Yellow Pages. You can also find psychologists who will conduct intelligence tests.

If there is any type of gifted programming in your school district, the school may be willing to test your son at no cost to you to see if he's eligible. I also advise parents to contact the psychology department of a local university to see if they will be willing to test a child for a lower fee as a means of training well-supervised psychology students.

You are ideally seeking a Wechsler Preschool and Primary Scale of Intelligence to be given to your son. As I always advise, ask first if the examiner has experience with both gifted children and young children. Good luck.