We started the kids at the age of ten. 4-H felt that younger kids did not have the concentration to handle guns properly. My wife actually started our son shooting at the age of five, but his Mother was very involved and it was one on one training. She stressed safety more than anything. One of the things I tell Anti Gun Mothers, or Mothers that are skeptic about letting their kids be near guns is, "Would you rather have your kids learn about guns in a safe controlled environment, or in some neighbors house with another kid that knows nothing but where Dad keeps his guns"? At this point they reach for the sign-up forms.
Check to see if there is a 4-H shooting program in your area. Or see if there is an approved NRA shooting course in your area. While at it if you can find an NRA Organization maybe you can have Eddy Eagle come to your Cub Scout meeting and give the NRA safety talk to the kids. Check with your local Fish and Game office, they usually have a Hunter Safety Course geared to young people. Most are either the NRA Course or something close. Any of those organizations should have material that either they check out or will let you bring the kids and watch the material. Here in Fairbanks I taught the NRA Gun Safety Course under the 4-H program. Unfortunately our club house burned down, and all our training supplies were lost. The info we had was all on VCR tapes we got from the NRA. I'm sure they will be getting all new material from the NRA, and that the new material will be on CDs. I just have not been involved since the fire.
The training we gave was the NRA Gun Safety Course, for the first four weeks. Then we taught the Alaska Hunter Safety Course for the second four weeks. During both segments the kids would have class room training for the first hour, then they went to the range downstairs and shot for the second hour. The Club furnished the guns, or the kids could bring their own. I did the class room training, I never worked on the range at this program. I have taken kids from the 4-H program that showed interest out to the local Skeet Range. You want to see a kids face light up, watch them when they bust their first clay bird.