I am fundamentally opposed to unpaid internships (you get what you pay for, and frankly I don't want to work with people who value their work as free), but there is an interesting blog post from Mark Cuban about the illegality of free internships: The U.S. Department of Labor has outlined a list of criteria that ALL must be met in order for an internship to be unpaid.

The Dept of Labor outlines what a free internships should entail:

1. The training, even though it includes actual operation of the facilities of the employer, is similar to that which would be given in a vocational school;
2. The training is for the benefit of the trainee;
3. The trainees do not displace regular employees, but work under close observation;
4. The employer that provides the training derives no immediate advantage from the activities of the trainees and on occasion the employer's operations may actually be impeded;
5. The trainees are not necessarily entitled to a job at the completion of the training period; and
6. The employer and the trainee understand that the trainees are not entitled to wages for the time spent in training.