baseballdad,
I'm right there with you. A bit new to the forum myself, I wish I would have found it years ago. DD5 started K this year, I of course new she was too advance for the class, but didn't have her tested until her teacher suggested it.

They did a "Brigance Comprehensive Inventory of Basic Skills" This does not give an IQ but it does let you know what grade level your child is at. Example, My daughter is a 5th grade level reading, begining 2nd grade math (although that was a month ago and now she knows most of her times tables including how to do more than 3 numbers and division which is 3rd grade)

Anyway It gives you an ideal were he's at and what to discuss with the teachers on why type of work they will give him. If you have it done before you put him in school it will also give you a chance to make sure the school is going to be a fit for him.