There is a new app in Marketplace called RealTube that lets you watch video from multiple sources, including YouTube and CNN in hi-def and over a mobile connection. This is not a browser based app. Instead it is from swflight who have created a Flash to Silverlight converter. Neat trick. And it works. I just tried a few videos and they were all buttery smooth even over 3G and the start time was on par with the native app. You can search a specific site within their app or just let it find content where it finds it. The only downside of this method is that if someone emails you a youtube link you cannot open it in RealTube. you need to open the app and then hunt the video down. Still it is high quality and works great. It’s $2 and has a trial mode.