At our club, any youth who comes out to shoot clay games is given 2 free rounds of birds, and 2 free boxes of ammo per visit. We also have a youth sized 870 Wingmaster for their use if they don't have a gun.
We have 2 club members who were Junior National Champions in Trap (though only 1 is an active trap shooter these days.)
Heading into 2010 we have a new volunteer who wants to spearhead Youth Programs at our club, so I hope to drastically increase the volume of Youth shooters next year.
Good luck to you and your son!