Well for Flash 10 support on your device, I think that you will be the luckiest guy on earth if you find it... or a really clever guy if you do the porting yourself
Nonetheless, you still have some workaround to be able to get youtube videos. For example you can use their mobile site: m.youtube.com if your device is able to decode .3gp or .mp4 videos. Or if your browser has HTML5 video support, you can try youtube HTML5 version:
http://www.youtube.com/html5
Of course there are some flash videos on some less known sites which do not provide such alternatives... and in such a case, I do not have any solutions :'(