Check out this informative video tutorial from Apple on how to stream music wirelessly with AirPort Express and a Mac. If you have a Mac or a PC and iTunes, it's easy to stream music wirelessly. It's called AirTunes. All you need is an AirPort Express and a set of powered speakers, or stereo, or AppleTV, and the room you want to hear music in.
And with the free remote app for iPhone and iPod Touch, you can control it all from anywhere in your home. See how to set up the AirPort Express and see how to use your iPhone or iPhone Touch as a remote.
Mac OS X is the world's most advanced operating system. Built on a rock-solid UNIX foundation and designed to be simple and intuitive, it's what makes the Mac innovative, highly secure, compatible, and easy to use. Quite simply there is nothing else like it.