Every game that uses 3D models as it's underlying technology (which is probably 95% of alle PC games released today) are able to be displayed in true 3D with the technology from Nvidia for example. So this really isn't anything developers have to do for themselves. Using the Nvidia system any Direct3D application that runs in fullscreen mode will be displayed in true 3D! They have to pay attention to several details though if they want the 3D impression to be accurate and not painful to the eye. I don't know if Firaxis has done anything in that direction. Anno 1701 (1701 A.D.) for example looks gorgeous in true 3D and the whole 3D hype hadn't even started yet when that game came out.