how to become a fishing guide?

i want to become a fishing guide in north carolina. id like to guide on fresh or salt water. how do you become certified to cary passengers?. is there a school that teaches you how to be a guide? how old do you have to be to take people out fishing on the water? what type of boat is good for inshore fishing? which brings more clients saltwater or freshwater fishing? how much should i charge for a half day of fishing?