The Macbook Airs listed on BestBuy.com are apparently "Not Available" for shipping. Amazon appears to be running low in certain parts of the world, too. This jibes with news we've been hearing about an imminent MBA refresh with Sandy Bridge processors.
9 to 5 Mac has also been hearing tell of a launch the week of July 4th, but that rumor goes unconfirmed. It can't be much longer now. [9 to 5 Mac]