So... I'm probably the millionth person to discover this... when buying a MBP the "line-in" can't work with regular headsets because it doesn't give any power (aka like a mic-in port). Then...hilariously I installed windows via bootcamp, and Apple's own windows driver allowed me to use a microphone in that port. That's right... I can use skype, play games, all with a microphone plugged into that port. The same mic that won't work under OSX, and it works just peachy. So... this proves it's NOT a hardware issue, it's a driver issue. The soundcard is perfectly capable of using a microphone through that port. The same mics that don't work under OSX. I love my MBP but that is just stupid. C'mon apple, enough with the oddities I'm sure it's not that hard to auto-detect the type of device and give it some amperage (like it does in Windows, using the driver that YOU supplied). /end of rant Now if anyone knew of a software patch, add-on, etc, that fixes the issue under OSX, that would be a godsend. I already bought a USB headset to use under OSX, but it really bothers me (out of principal) to need to use it after discovering this.