Did anyone try this link?

http://videolinks.nokia.com/site/europe/

On my desktop it takes me to a list of Youtube videos and it's obviously formatted for a mobile screen. I don't have my N800 with me, but if I did I think I could simply click on one of the video thumbnails to see if it's supported. The video format isn't recognized on my desktop.

Note that this is the actual web pages, not a service catalogue. It gives you a very good idea of what the service looks like anyway.