Steam is a great application that is basically an iTunes for games.
They released it for Mac a few months ago, and since then the creators (valve) have been porting their own games and selling them on their.
Since the release for Mac,the Mac game library has been growing and growing.
Edit: I can tomorrow. Send me an email with your username so I can add you so and so i dont forget.
its a portal for downloading and playing games as well as a great newssource for upcoming games/events and it patches and updates all the games in your library automatically as well as give the player some other achievements to complete.
among other things, if youre new to mac and gaming its a must.
Watch out for their sales, they can get very nice pricing on games. I picked up the complete Civ IV (base game, 2 expansions and colonization) for the princely sum of $9.99. Everywhere else still sells the Mac version for something like $39.99 just for the base game.