I just bought a macbook a few days ago. I'm totally new to it and therefore a complete dumbass. So.... I want to start using my guitar with Garage Band. I know I need a 1/4" to a 1/8" adaptor. (In the process of buying one). However......... Where do I plug that into? On my Mac there is definitely a headphone jack-in. But there doesn't seem to be a mic jack-in. Is it the same thing? Or do I need to buy something like this? http://www.turntablelab.com/dj_equipment/41/49/68301.html Cheers dudes.