I've done a quick screen shot here:
I think you may have to follow #newtwitter before getting an invite to view the new look.
But as you can see the bar at the very top now has the search box, home, profile and messages links. Below shows whats happening on the left, and to the right displays other info about you and new trends, etc.
Even though it does look very nice it's the background I'm concerned for businesses it was a way of free advertising.