The new Trine 2 beta on Steam now offers cross-platform co-op multiplayer support in the platformer sequel courtesy of Valve's Steamplay service. Those interested in the beta can gain access by pre-purchasing the game. Thanks Joystiq.
_________________________________________________ "Money doesn't exist in the 24th century, the acquisition of wealth is no longer the driving force in our lives. We work to better ourselves and the rest of humanity." - Jean-Luc Picard