I recently acquired an Apple Airport Express with the intent of wirelessly broadcasting music/audio from my computer (one side of the room) to my home stereo system (other side of the room) using the AirTunes functionality. This has been a good solution for me as it’s designed for iTunes and that’s what I primarily use to play music on my computer.
First, you need to install the Airport Express. This can be a difficult process depending on your level of experience with wireless networking; if you’re having trouble, visit the Apple Support page for the AirPort. To use the device, begin by running the installation software that comes with the device (or download it from Apple) on your computer. You will also need to connect the Airport Express to your stereo; for this, you can either use a 1/8″ to RCA connector or 1/8″ to Optical/Toslink connector and hook it to your stereo receiver or other audio input.