Details of the new FPS will be unveiled in the August issue of Game Informer, who have been granted an exclusive. So far all we know is that the game will heavily feature a morality system. Missions will grant you the option of proceeding through them with stealth and not killing anyone, or you can set traps and kill countless people. The actions you choose will have an impact in the game and how it unfolds, as well as how others treat you.
The developers of Dishonored, Arkane Studios, is a French-based developer that was founded in 1999. Its first title, Arx Fatalis went on to a small cult following. After that it co-developed the game Dark Messiah of Might and Magic, and then lent a hand with the level design of BioShock 2.
From the brief description, Dishonored sounds interesting so far. No exact release window yet, but it will be out for PC, PS3 and Xbox 360 in 2012. Expect to hear a whole lot more on this game soon.