The upcoming Game of Thrones MMORPG is currently being developed by BigPoint (http://www.bigpoint.com/) in collaboration with HBO. BigPoint is already one of the premier developers of online games, including Battlestar Galactica Online, and Lord of Ultima. Now, in partnership with HBO, and based on their award winning television series, BigPoint is working on a Massively Multiplayer Online version of Game of Thrones.
Venture Beat (http://venturebeat.com/2012/02/29/bigpoint-unveils-game-of-thrones-online-game-based-on-hbo-series-exclusive/) got an early look at the game, including a few screenshots and some discussion about the focus of game play, noting that both combat and politics will be vital to the players success.
To sign up for updates on the game, go to their official Game of Thrones website (http://gameofthronesmmo.com/).