There is now an official Mortal Kombat desktop widget, which has been released as a GameStop exclusive. From this widget, content from the official Mortal Kombat site is available, including several images and all of the trailers that have been shown up to this date. Right now, two characters are available – Scorpion and Sub-Zero – with four more locked slots prominently displayed, presumably there will be at least four more characters to be added later.
To install the widget, visit here.