The slimserver software will allow you to synchronize music to various PCs, or a combination of some synchronized, while others playing different music. The software is open source and quite well done. If you want to use PCs as a front end rather than squeezboxes, you will have to install softsqueeze on the client PCs. As the name implies, softsqueeze is a software interface that mimics the squeezbox, including the remote control. I currently have one Squeezebox, with another on the way. Download slimserver and play around with it, it's the best streaming audio player I've used.
