HD Web Content & HD MMS?

I was wondering how do I watch web content in HD on my iphone, particularly youtube? I have this fantastic screen that i can't see anything in quality resolution with unless i buy it from itunes, upload it to my phone, or record it myself. I have seen other phones switch to the higher youtube resolution right on the player and it comes out crystal clear. Is there a way to do it on iphone 4?
Also whenever I shoot a video and try to send it thru MMS it is severly downsized to wat seems to be the crappiest resolution ever. How do I avoid that when sending videos? It says clearly on the apple website that you can share your HD videos over MMS. Thanks!