http://www.megsss.org/index.php?option=com_content&task=view&id=31&Itemid=62

Here is the curriculum for an organization established in 1978 by mathematicians, scientists and engineers to challenge and train (only) the most highly able math students beginning when they are as young as 4th grade. The organization�s mission is to identify and instruct the most promising future scientists. At least in the St. Louis area, far more than 1 in 1000 kids qualify for the lessons based on their results after a battery of math achievement, math aptitude, logic and reasoning tests. Many graduates of this three-year program do test into pre-calc as freshmen when they enter either public or private high schools and continue on to prestigious universities.

I wish I had known about it earlier for my son.

Kristen, I had thought this might be a good home school curriculum for your son. I don�t know if you can buy the books anywhere though.