It's Modern Warfare week for co-op gamers with Modern Warfare 2 hitting the 360, PS3, and PC with it's two player Spec-Ops co-op mode and Modern Warfare Reflex hitting the Wii with it's two campaign co-op mode.
Modern Warfare 2 offers two player split screen and online co-op through 23 missions. These missions are quick offerings that differ from the story and offer various objectives like racing, survival, and laser targeting. There's three versions of the game to choose from with normal, hardened and night vision goggle edtion. [Get it @ Amazon]
Modern Warfare Reflex offers two player same screen co-op on the Wii through the story of the first Modern Warfare title in this shooter. Player one has full control while player two has their own cross hair and limited control. [Get it @ Amazon]
Phantasy Star 0 offers four player co-op via local wi-fi or online via the Nintendo Wi-Fi connection. Players team up to complete quests, chat with "visual chat" and take part in three different modes of play. [Get it @ Amazon]