We're big fans of Creative Commons licensing, so the news that YouTube is now allowing users to upload their videos under a Creative Commons licence is welcome. If you're happy for your video content to be used and repurposed by others (with attribution), it's a great step forward.
Google Operating System notes that when you upload a video, you can now elect to use Creative Commons rather than the standard YouTube licence. The default option is the YouTube one, so you won't end up changing your rights summarily, but it's nice to see it there.
Creative Commons Videos on YouTube [Google Operating System]