I had a friend who has a old G4 Powerbook. He can play music to his stereo wirelessly. I looked into is and only found the Airport Express is the only way to put music to his stereo. AND he isn't using a airport express. I seen the box but don't know what it is. it is black. My question is there any device to which I can play my music wirelessly and that is compatible with Mac OS X and Windows XP, which both are using itunes 8, and it isn't an $100 Airport Express?