How do i use the Steel series 3gc with my mac?

Check out their supoprt page > SteelSeries North America - Support

Yes, I believe the product is not Mac Compatible. Mac Compatible running Bootcamp, probably.

Which of your products are Mac compatible?

and

Yeah--I had the same issue with this and the Gigiware game controller from Radio Shack. I buy them, open them and after it doesn't work, I look up their support pages and there's no support. The only problem is that their packages both claim the controllers to be PC and Mac compatible! Why do they make that claim on the package and refute it online? Unless there's supposed to be some sort of game sprockets plug & play driver on the Mac side that is no longer.

Solved: There is no driver to install. If the lights come on for your controller, the drivers have successfully been installed and the controller is ready for use. But before you can use it you must buy an app called "Joystick Mapper" from the Mac app store ($5). This will allow you to program the individual buttons' functions per the game you're playing. You will need to program multiple profiles if you plan on playing multiple games, as all games do not share the same button configuration. Also, you can clone game profiles. So if you're playing a shooter, for example, where the zoom and weapon fire buttons may be the same but there's a different button for grenades or secondary fire, you can tweak a few buttons instead of starting over from scratch.

I know this is alittle late but i ran into the same problem that you had with this product (steelseries 3GC) claiming to be mac compatable but once i got it home it didnt work. What did work was a program called USB overdrive it was easy to install and once i entered all the buttons in it worked like a charm and best of all its free!!

http://www.usboverdrive.com/USBOverdrive/News.html

enjoy!!