We have discussed internships before.  And recently the DLSE amended its view.  To avoid wage & hour problems, internship programs should adhere to these rules:

The training, even though it includes actual operation of the employer’s facilities, is similar to that which is given in a vocational school.

The training is for the benefit of the trainees or students.

The trainees or students do not displace regular employees, but work under their close observation.

The employer that provides the training receives no immediate advantage from the activities of the trainees or students and, on occasion, the employer’s operations may even be impeded.

The trainees are not necessarily entitled to a job at the conclusion of the training period.

The employer and the trainees or students understand that the trainees or students are not entitled to wages for the time spent in training.

Basically, the DLSE tightened its focus of this issue by dropping the previous "11 factor" test.