Sorry, I guess I over anticipated people to know about it.
It's created by the same group that makes Baldurs Gate, Bioware, and is run on an incredible engine. It's an RPG, and plays similar to Baldurs Gate and the D&D rules, but is all live action and no turn-based battles. What makes it so different is the game creation kit that comes with it, allowing you to create your own massive worlds and very easily also, not like any other editor (such as Morrowind) that requires tons of scripting. These custom built worlds can then be played online with up to something like 85 different people in your game. I believe there is a server up for it also. Thats what I know from it right now
Here are some screenies:
http://image.com.com/gamespot/images..._screen001.jpg - In game shot
http://image.com.com/gamespot/images..._screen007.jpg - Editor
http://image.com.com/gamespot/images..._screen010.jpg - Editor
http://image.com.com/gamespot/images..._screen013.jpg - Editor
http://image.com.com/gamespot/images..._screen019.jpg - Game
http://image.com.com/gamespot/images..._screen023.jpg - Game
http://image.com.com/gamespot/images..._screen031.jpg - Map Editor
http://image.com.com/gamespot/images..._screen008.jpg - Game