Good news today for those of you on Apple's platform that like to conquer the world - Civilization V is available to purchase as well as download via Steam. While the game originally was unconfirmed to offer Steamplay support, that means you can run the game on either Mac or PC just by purchasing either version, Aspyr Media have announced full Steamplay support at launch.
There are a few quirks though - Steam Cloud support isn't enabled for online saves as well as cross platform saved games aren't compatible with each other. The good news is it sounds like the publisher is working on fixes for both. Whether you purchase a retail copy or a digital copy online you'll get the same Steam integration regardless of platform.
Civilization V offers a three player online co-op mode where players can team up against the AI, share technology and research, and of course...conquer the world in just one more turn.