Besides the new YouTube Remixer, YouTube also launched a mobile version of its website.
The mobile YouTube can be found at m.youtube.com
When you go to it you first get a warning that YouTube Mobile is a data intensive application and it recommends you to upgrade to an unlimited data plan with your mobile service provider in order to avoid additional charges.
The mobile YouTube doesn't use Flash, the videos are played in the built-in media player of your smartphone. Only phones that support streaming video RTSP/3GP with H.263/AMR are supported.
Another important issue is that not all YouTube videos are available on the mobile version. Only a select library of YouTube's videos has been converted for the mobile version.
I just tried YouTube Mobile on my HTC S710 Windows Mobile 6 phone but it didn't work. Windows Media Player refused to play the videos.