Thanks to HarperCollins Voyager, there’s now an A Dance with Dragons app for those with iOs devices! According to the description, the app contains an extract from the novel, a quiz to sort you into a noble house, a chance at a prize draw, and more.
The official release date is July 12th, with Kindle and Audiobook editions being released simultaneously. Some more information, and pre-order links, can be found here.