When I was in college employers contacted the school when they were looking for workers. The instructors had boards with job listings from different companies that he updated a couple times a week. You could look for local colleges and tech schools in your area and see what areas they teach and possibly get in contact with an instructor.
I second that. Here our human resources / career services are always looking for jobs to help students out. If you can get in contact with a college and tell them you are looking for a student intern for the summer, I'm sure they'd be more than happy to help.