I need to use a headset with my Powerbook. I tried plugging one into my Powerbook but couldn't get the mic to work with the line-in port. I also tried playing with the settings in OSX but it didn't work. It might be the fact that I bought a crappy headset but I haven't had the chance to try another yet. Does an external mic work with the line-in port? Any special settings I might have missed?