Will just any old pc mic work in OS X? I would like to buy a couple mics, one for a PC user and one for my mom who uses my old mac mini (no mic on those ). Do I need a certain type? What should I look for? http://search.ebay.com/pc-mic_W0QQfromZR40QQfsooZ1QQfsopZ3QQsbrsrtZd is what I'm looking at right now.