why would you want to do this to your child? The pressure that is involved is beyond normal.
Being out-going doesn't make your son a model. It makes him prey.
Does HE want to do this? If so? I would find an agent and then work with the agent. This is NOT free and it will cost you a ton of money. Agents aren't free.
When I see the little girls in pagents that are 4 years old? My heart breaks. Those girls never get to be kids, it seems. They grow up learning "how to be pretty".
Prepare yourself, your bank account and your son for this. It's WORK. It's NOT play. Think about the long term affects. If he makes it? Look at the struggles that child stars go through: drugs, alcohol, binge eating/bulimia, and more. think this through before you do it.