Annenberg Media has free streaming videos--requires sign up. Excellent content for professional development. According to their website: "Annenberg Media's multimedia resources help teachers increase their expertise in their fields and assist them in improving their teaching methods. Many programs are also intended for students in the classroom and viewers at home. All Annenberg Media videos exemplify excellent teaching." Resources are divided into six broad disciplines and are browseable by grade.
Education at Alexander Street Press focuses on the development and training of teachers. Content includes primary-source footage of students and teachers in actual classrooms, demonstrations, lectures, and documentaries to help both new and experienced teachers develop their abilities to teach, mentor, understand, and communicate with students of all levels of need.