You have some good advice already to get Iowa Acceleration Scale and Nation Deceived.

Also, I would suggest reading up a bit on the idea of a Gap Year. My son is grade skipped and young for his grade anyway. We plan (though plans change!) that he'll do a gap year or possibly a 5th year overseas as an exchange student before college. If he's ready at 16 to do college, then that's fine but if not we have options.