According to reports, Apple is prepping an upgrade to its MacBook Air line due to hit on July 19th. So if you were planning on picking one up, you might want to hold off.
We're expecting a Thunderbolt port, some fancy new Intel Sandy Bridge processors, and Apple's new OS X Lion built right in. As for those processors, "Apple will likely offer Intel's 1.8GHz Intel Core i7, 1.7GHz Core i7, and the 1.7GHz Core i5." The form factor should stay the same.
Those are some pretty beefy chips for computers this thin and light. Are we approaching the time when the MacBook Pro becomes unnecessary, and the Air is Apple's flagship laptop? It seems that way.