I doubt there is an international association of runners that goes around policing these things. You probably just have to find one, then sign up for it.
Nope, just sign up. They want your money.
Tell me about it. It was $90 bucks to sign up, fees for parking, shuttle, etc. I felt a bit raped.and pay the entry fee, which is the only thing keeping you from running any marathon or half marathon you want.