A friend of mine works for a non for profit organization and works over 40 hours a week and doesn't get paid any overtime.

How would I go about helping her let this be known.

What do you want to help her do? Confront the employer or file a claim? Has she asked the employer why she is not getting paid overtime? What do they say?

Are you sure she is nonexempt (eligible for overtime)?
http://www.moga.state.mo.us/statutes/C200-299/2900000505.HTM