Full episodes, podcasts, and video clips.
NOVA is a site mostly dedicated to science and related fields of study. It has resources to help you include video into your classroom units and activities. Each part of the lesson has video along with suggested discussion questions. All videos in all subjects can be incorporated into the curriculum and meets the correct standards.
Main Site: http://www.pbs.org/wgbh/nova/
Teacher Site: http://www.pbs.org/wgbh/nova/teachers/lessonideas/index.html