YouTube Mobile goes live
YouTube Mobile is a streamlined version of YouTube made to run on mobile phones. Videos can be streamed by any phone capable of viewing RTSP/3GP files with H263/AMR.
When you first navigate to YouTube Mobile, you're greeted with a warning that you may want to upgrade to an unlimited data plan before using the data-intensive service. Currently only a limited number of videos are available, but you could always use a third party service like Orb to access the entire library of YouTube videos from your phone.