On the heels of a previous agreement with Verizon Wireless, Square-Enix U.S.A. announced on Sunday the opening of an exclusive gallery service in cooperation with AT&T Wireless.
The "Square-Enix Gallery" is the first exposure that the Final Fantasy series has received in the North American mobile phone market, following a successful year-long run in Japan. It allows users of AT&T's mMode service to download one of over 200 wallpapers featuring a variety of characters from recent Final Fantasy releases, including Final Fantasy X, X-2, and XI. A few examples can be found here.
These wallpapers can be downloaded for $1.99 a piece, but Square-Enix has promised a wider array of choices to come in the future. You can find information on this service at Square-Enix's official mobile techonology site and at AT&T's official site for mMode.
[Sources - AllRPG, RPGFan]