I ran across this looking at the PBS Teacher Previews. What a resource!
Listen and Learn
The WGBH Forum Network Offers On-Demand Lectures from World-Renowned Scholars Online
Grades 6-8 / 9-12
Educators have an audio and video library of scholars, authors, artists, scientists, policy makers and community leaders at their fingertips with the WGBH Forum Network, a free resource that offers audio and video streaming lectures from leading authorities. With partners such as the Harvard Graduate School of Education, the MIT Technology and Culture Forum and the Boston Public Library, the WGBH Forum Network has recorded hundreds of lectures that can be used in the classroom or for your own professional development. In addition to subjects such as history, literature and technology, the lectures include a series on issues in education.