Most enterprises and companies today are interested to put up websites that render well on mobiles. Not every website can render properly on a mobile/smartphone screen. Some look terrible because their layout gets all jumbled up on a smaller screen size. Text becomes unreadable, buttons get hidden and menus look ugly.
So a lot of effort has to go into making a website render beautifully on a mobile.
Here is a list of 30 sites that are mobile optimized and look good on any mobile screen.
http://www.topdesignmag.com/30-examples-of-mobile-optimized-websites/
And here are 10 most viewed mobile sites of the year 2011:
http://www.opera.com/press/releases/2011/12/20/
More examples including that of stunning designs are over here:
http://www.mobileawesomeness.com/