Right click on the folder that contains all the music and click PROPERTIES, select the SHARING tab at the top of the properties box and select the check box that says "share this drive on a network" and the box that "allows users to change the content of the drive/folder" or something along those lines. Select a share name, like MUSIC FOLDER or something like that. Then apply all changes and restart ALL pc's on the network, check "My Network Places and the MUSIC FOLDER should be in there, any changes made will all be in one central position. One downpoint to this method is that if your PC is turned off then NO PC's will be able to get to the music, thats when a dedicated file server comes in, but for "normal" home users, a file server is out fo the question.
I have a streaming audio server broadcasting wirelessly 24/7 using ShoutCast. Kicks some major ass if you ask me. Its used for music but you can easily upload a quick file or two to it.