Well, I'm not sure about watching Youtube from within the browser, but it is possible to watch some Youtube stuff on your palm.
I have recently picked up Kinoma Player4, which is an audio & video player, but it's main capability is that it can stream audio and video from the internet. The program has a media library that is basically selection (albeit a very large selection of probably thousands of audio & video streams) of channels and stations. They do offer youtube videos right through their media library (which is updated from Kinoma's website over the internet).
It's hard to explain, maybe go check it out at
http://www.kinoma.com/index/Player4.
Also, there is a mobile version of the Youtube site called mobetube.com, and also mobile Google videos at mgvids.com. Check both these sites for more info about what is needed to stream from either Youtube or Google.
I like Kinoma because it's easy to use, works well (although you can't stream audio in the background like you can with pTunes), and is only $25.
Good luck!
