you'll find some answers here: http://webapps.stackexchange.com/q/22367/12672 People are saying you need to first install the iPhone app but I don't think it's necessarily the case.
Dear Friend, what you suggest me I didn't get over there what I am looking for? I want to know how to switch new twitter look ?
They usually have a link at the top that asks if you want to switch to the new look.. If you don't see it, chances are it's Beta and they only selected random accounts.. I've gotten the new account but mines switched automatically.. I think.. Let me know at @iblog4dollars if I got the new account.. Looks pretty new to me but I'm always using twitter from my iPad on Tweetcaster..
Yes I agree with Dennisknows, there is always a link at the top that asks if you want to switch to the new look just like in other social network sites. Some times some sites automatically change the look with new version like youtube , gmail, orkut etc
Since today, my Twitter account has directly switched to New look, even i tried but i couldn't figure it out. Just trying to get my old Twitter back.