In addition to having digital video and photographs resources on their own web site, The Library of Congress now has dedicated channels on Flickr and YouTube!
YouTube: The Library of Congress Channel currently has six channels, or play lists, featuring the 2008 National Book Festival, Books and Beyond, Journeys and Crossings, Early Films - Westinghouse 1904, Kluge Center Series - Prominent Scholars on Current Topics, and Early Films - Edison Companies.
Flickr: The Library of Congress Photostream currently has five collection sets with thousands of photographs available to the public. Included are Women Striving Forward 1910 - 1940 (23 photos), Abraham Lincoln (22 photos), Photocrom Channel views (169 photos), World War I Panoramas (15 photos), 1930s & 1940s in Color (1615 photos), and News in 1910 (3950 photos).
According to the Library of Congress blog, both projects are ongoing and collections will continue to grow and evolve.
Read more about the YouTube project: Library of Congress Blog: YouTube and Now We Do Too.