I started programing when I was 6 - with a little help from my Dad
Mostly I learned from a book about programing Space Games. This was back in the days of Basic though.... on a System-80 clone.
I always wanted to be a programmer! It didn't really happen though (but I do work in IT).
I suggest downloading Visual Studio Express - its free, its from Microsoft, and you can do real programming in it.
He will probably get more opportunity to do programming once he gets to highschool.