All you need to do is:
→ buy an airport express (or two, or three) from Apple
→ plug speakers and/or your old stereo into said Apple gizmo
→ if your mac supports wireless, simply select "multiple speakers" in iTunes and you're set for full-house-acoustic-action
→ if your mac does not even know what wireless is, like mine, connect the airport expresses by about twelve ethernet cables strung madly about the basement, then proceed as described above
I give this pitch for Apple products despite my diminished quality of life following the demise of my office mac. Though I swore at least one vendetta against Apple, and very much enjoyed my loner pc with the built-in "I'm watching you!" camera, if there's one thing I learned in my undergrad ethical theory course it was that failing to fulfill the promise of a vendetta is okay.
This home network complements another iTunes network I enjoy at work—this one consisting not of multiple play zones but a vast archive of shared music files. Every mac user on the network who openly shares their iTunes has access to this archive, and at any give time there are about six zillion songs you can listen to.
If you thought reading your colleague's blog was revealing, try perusing his or her music collection.