The Scrabble app for iPad will work with the iPhone, displaying the players' letters on the iPhone screen.
In the New York Times's iPad review, David Pogue explains that the iPad edition of classic boardgame Scrabble will come with a free iPhone app called Tile Rack.
This app will allow players to view their letter tiles on their iPhone screen in private, rather than on the iPad screen.
Not only will it be possible to shuffle your letters around on the touchscreen, but you'll then be able to flick the tiles from your iPhone onto the board on the iPad screen.
Such a simple idea, yet so utterly brilliant. Hopefully this is the first of many such iPad-iPhone app interactions.