YouTube has released a version of their mobile application for most Windows Mobile and S60 handsets. The new application allows YouTube to play
on some phones that previously could only see videos from the mobileYouTube site on their browser. One of the major improvements has been in terms of speed with YouTube loading, searching and downloading videos as much as 90% quicker than the streaming videos that come from the mobile site.With the service automatically optimized to your Wi-Fi or 3G network, picture quality is improved. The application will also alert you when new updates are available and allow you to upgrade with a single click. To download it, go to m.youtube.com.
source: YouTube Blog