Using A Gamepad with my iMac

Hello All,

I have a 2.7 GHz Intel Core i5 iMac and have recently bought a copy of "The Witcher 2" from the apps store. As I suspected, it isn't very playable with a mouse and keyboard. I've heard tell you can use a gamepad on your computers. Is this just a PC thing or can I do this also? If so, how is this done? What sort of gamepad can I use (my xBox 360 controllers, perhaps?) Will it just be plug and play or do I need to go on a hunt for additional software?

Thanks for any advice/words of wisdom.

Brian