Apple AirPort Express v4.2 - Manual (Page 18)

18 Using AirPort Express
To join the wireless network, use the AirPort status menu in the menu bar on a
Macintosh. On a computer using Windows XP or Windows 2000, hold the pointer over
the wireless connection icon until you see your AirPort network name (SSID), and
choose it from the list if there are multiple networks available.
There are also other ways you can connect your AirPort Express to your home stereo.
If your computer has an AirPort Extreme Card installed, or a compatible wireless card
for Windows XP or Windows 2000, you can use AirTunes to play iTunes music on a
stereo connected to your AirPort Express.
DSL or cable
modem
to Internet
Stereo receiver
Line Out port