Robert,
I see our interns as our top people down the road. We use our internship as a way to support people as they save for or go to college. We want top notch people working with us who are engaged in building the business. It is hard to get most people real engaged unless you are compensating them in some way.
I think it is appropriate to pay them at or near minimum wage to start as the company needs to invest in them to get them up to speed. As they start to contribute more and learn more we structure their compensation so that they can make more. In my opinion one of the best lessons you can teach someone is that,"you eat what you hunt and kill" in the work place. I think a performance based compensation and a clear path of advancement encourages growth.
Anyway that's my two cents.
Ron