This article dismantles so many arguments that I hear all the time that piss me off to no end. A lot of the logic used to justify unpaid internships is similar to the logic used by employers who justify underpaying their employees. A little while ago, I made a thread about how ridiculously underpaid most legal assistants are, and how they're basically asked to be 80% of what a paralegal is for about 1/6th of the pay. And some of you suggested that it's okay because of the experience you're gaining!
Also: see this link for more info:http://internjustice.com/