Wikimedia Commons is a media file repository making available public domain and freely-licensed educational media content (images, sound and video clips) to everyone, in their own language.
Launched on 7 September 2004, Wikimedia Commons hit the 1,000,000 uploaded media file milestone on 30 November 2006 and currently contains 7,579,255 files and 99,182 media collections.
Unlike traditional media repositories, Wikimedia Commons is free. Everyone is allowed to copy, use and modify any files here freely as long as they follow the terms specified by the author; this often means crediting the source and author(s) appropriately and releasing copies/improvements under the same freedom to others. The license conditions of each individual media file can be found on their description page.
Browse the resources on Wikimedia Commons at http://commons.wikimedia.org/wiki/Main_Page