My 5 year old wants to be an author.....?

my 5 yr old has recently decided he wants to write and illustrate a book. he's already started on a pritty decent story and wants to send it into a magazine or something so other kids can read it. does anyone know of a magazine or web site that i could send his story to and try to have it posted? he's really serious about this endeavor and i don't want to discourage it. thanks in advance!