Automattically Genre songs in iTunes

Does anyone know of a program that I can run to take the songs in my iTunes library and give them a genre instead of going through and doing it manually? I am such an organized freak and hate not having this done...

Yeh I know what yeh mean im a organised freak like that too, but sadly i haven't found anything to help us . I just make sure everything sound from in the recently played playlist is all organised.