Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Good and Bad news:

icon13.gif
No it can't.
icon14.gif
YouTube's widescreen videos do play on tv. They now fill the entire screen, versus the square videos that we used to get.

I'm sure it's a matter of time before the tv firmware is updated and we get access to the HD videos on YouTube.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.