John Falcone already beat me to the punch with a detailed preview of Logitech's Squeezebox Duet, but I'll second his verdict: this looks like a more affordable competitor to the Sonos multiroom digital audio system, which I got a chance to experience in a real home environment last summer. In a nutshell: you connect the base station to any stereo with RCA inputs, and it draws music from your PC over a home wireless network, and lets you control it all with a handheld remote with a color screen. It supports every imaginable digital audio format, and is significantly less expensive than Sonos, starting at $400. More information's available on Logitech's site.
Optionally, you can use Logitech's free SqueezeNetwork, which automatically aggregates all of your Internet music services--subscription-based services like Rhapsody or Internet radio stations like Last.fm--and lets you listen to these stations even when your PC's off. It's one of the most interesting digital audio products introduced at CES, and I recommend stopping by the booth for a demo if you're here.