Well, he's not afraid of kids, that's the important thing. He just wants to play with 'em.
How's he on bite inhibition? Can you trust him not to chomp and just to mouth if he gets excited? And not to snap, at least not at faces? If you can then you don't have much further to go.
Look around and see if any of your family or close friends have kids who'd want to help out and who won't mind getting scratched up, knocked down, and slobbered on. (I dunno what the world is coming to. When I was a kid, if you got knocked down by a friendly dog and maybe scratched up a bit ... well, that was part of playing with the dog. You learned to pay more attention and how to redirect a dog in mid-jump.
And oh my god does that last paragraph make me feel like I'm getting old.)
But that's the best way. Find some kids for him to play with. If he plays too roughly, give him a command to chill out, and if he keeps playing too roughly, give him a time out for about a minute. If he goes back to playing at an appropriate level, give him a treat (or join in on the petting, or throw a ball, or whatever.) Since most dogs that love playing with kids really love
playing with kids, he should pick up on the drill pretty quickly.