3rdPartyAudioStream
From SqueezeboxWiki
This plugin should be able to route the audio from i.e. a portable pc where you're watching a movie. This way you can enjoy the sound from the movie even though the sound quality from the portable pc is poor.
An application has to be running on the laptop to stream the audio to the squeezecenter server. It might even be enought to stream the audio to a ip port, because the squeezecenter is able to tune in to an URL including a port.
I might try to do this my self, but only the time will tell.
This is moderately simple, however you are going to have latency issues. One way to do this would be to use VLC/similar to create an HTTP audio stream of the WaveOut loop of your Sound card, and pointing SBS at the stream as a radio station.
Did you have a look at the Wave Input plugin? That does what you want ... http://wiki.slimdevices.com/index.php/WaveInput_plugin
