The TEACH Act addresses the digital transmission of copyright protected materials in an educational forum. TEACH generally states that it is not copyright infringement for instructors to transmit lectures that contain certain copyrighted works if the work is used as it would be in a live classroom.
For example, if you display a painting or play a copyrighted song in class, the TEACH Act provides a safe harbor for podcasting and posting your lecture on a password protected website that may only be accessed by students in your class.
For information regarding works and uses protected by the TEACH Act, including a compliance checklist, see the University of Texas Copyright Crash Course: http://copyright.lib.utexas.edu/teachact.html