you want one game to play on both of the monitors. i have duals (used to have 4) but i played CS in a window not full screen im pretty sure in full screen one monitor goes black while the other has the game on it. it doesnt stretch to both screens.
i sent to play in windowed mode and set up the res but it doent play on both monitors.
if i sst my windows res way donw to 640x480 and civ 4 rez up it will cover 1 1/2 monotors but also the hight expands way to far off the bottom of the screen