This website from sociology graduate students at the University of Maryland; Valerie Chepp, Paul Dean, and Lester Andrist; features a blog and collection of video clips with discussion points that can be used in the classroom.
Be sure to check out the Resources section for sample assignments and a bibliography of scholarly research on video use in the classroom.
"Films For Action uses the power of film to raise awareness of important social, environmental, and media-related issues not covered by the mainstream news. Our goal is to provide citizens with the information and perspectives essential to creating a more just, sustainable, and democratic society. Our website has cataloged over 1500 of the best films and videos that can be watched free online."
Although not moving pictures, the website Sociological Images provides a similar treatment to photographs.
Additional resources for free online videos: