Around back, completely new taillights are the obvious change, while the front end gets 997 turbo-style intakes in the corners of the bumper.
Obviously, it's still too early to know when these changes are coming and if they'll find their way across the entire 911 range right away. As WCF points out, the just-announced Targa coming in November does not wear any of this new bodywork.
Chances are, however, that in due time all 911s will get the new look. History has shown us that even when changes are "exclusive" to some models (think of the 996 Turbo's headlights), they eventually are applied across the board.
Either way, Porsche aficionados have something to look forward to. For a gallery of full-car shots, head over to World Car Fans.