Contact your local university’s business, journalism or multi-media departments and ask them about internships. They’ll direct you to the instructors running the internship programs, who’ll get you the appropriate info.
The ‘rules’ are pretty standard for most schools, we advertise interships on our website(& sometimes with mass mailings to the schools). The students come in with the docs they need to get school credit, & we sign them upon completion of their internship.
Also keep in mind that calling someone an intern does not automatically exempt them from labor laws (including minimum wage laws). Scroll to the bottom of this page for more information.