Recently I came across a great resource online called TubeMogul. Located at http://www.tubemogul.com, this web service allows you to upload a video once, and have it be 'launched' simultaneously and automatically on a multitude of video-sharing sites like YouTube, Vimeo, Blip.tv, MySpace (ugh), and more. Anyone who has wrestled with all the effort it takes to distribute their video work to all the social networking sites out there will appreciate this tool. Tube Mogul also allows you to track views and other statistics about your uploaded videos on all these sites.
Of course, you need to have accounts on all the video sharing sites that you distribute to via TubeMogul, but once that is all set up, it's a great time-saver.