Google has released a YouTube app for most Symbian and Windows Mobile phones. Many Symbian devices already have a Flash-capable browser that can watch videos on YouTube, Google's app will likely provide a richer experience for wireless users.

Features via Google's Mobile Blog:

More phones: Supports most Windows Mobile and Nokia S60 devices (a list of supported Nokia S60 devices is available here).

Speed: Faster application start-up, searching, and video loading. For even quicker access, add the application icon to your phone's home screen.

Video quality: The application automatically detects your device and network capabilities, and selects the highest available stream quality based on those. Videos will look sharper and sound clearer than ever.

WiFi: Improved streaming over WiFi to support a wider range of networks.

More robust streaming: Improved buffering ensures that videos will play even in weak coverage areas.

Easy video viewing: Once installed, no configuration is required outside of the application. We've worked really hard to make video playback "just work".