Good article Pax... you're sight is becoming a wonderful resource!
My standard saying is 'our objectives today are (A) to have a good time, and (B) to go home with the same number of holes in you as you arrived with.
One more recommendation: Keep the first range trip short, leave while the child is still having fun. Telling junior to sit in the car while daddy runs through another hundred rounds is _sure_ to ruin the experience.
I have 4 daughters, aged 11-20 now. Each started shooting somewhere between 9 and 11, depending on how ready I believed them to be. All are now fairly proficient shooters, with a good understanding of firearm safety. Two of them really enjoy shooting, the other two will go once in a while. Don't force it, shooting isn't everyone's favorite activity, but _everybody_ should have a good practical understanding of firearms and firearm safety.
Oh, the recommendation of no more than 1 kid per adult for the first trip, and 2 kids per adult after that... you're right on the money with that one.