Hi, playing with a imac g4 (OS 9.2, yeah, it's a long story) to try to get some anolog stuff on CD. there's a way to switch the speaker out to line in. how do i find it? I'm a total newbie to macs so I need all the gory details like what to open, etc. also, Macs use a special sized speaker plug? I'm running desk top speakers now through the headphone jack.