www.allaccess.com is my favorite website for broadcasters. You have to register but it is free.
www.collegebroadcasters.org has a jobs link under their "CB Resource" page.
www.clearcareers.com - Sorry, that is Clear Channel but it still can go on a resume.
Most of the internships fall under Promotions, and is the equivalent of slave labor, but there are some cool things out there, too.
Good luck!