[LAD] Playing Audio Over CAT5

Hi, I am an undergrad student working on a project related to playing audio on a Linksys WRT54GL Router through cat5 cable. I have the following setup. A Linksys WRT54GL router with OpenWRT firmware on it. What i want to do is to play some audio file (prefrably mp3 format), and stream the output over Ethernet through CAT5 cables and convert it through a balun. I have broken the process in following steps 1. Get the audio file and decode it (through libmad or a similar library) 2. Convert this to analog form 3. Send it over Ethernet I understand the first part, and have already started the implementation, but the other two steps are where i have problems. To play it directly on a speaker i would need to convert it to Analog, but how do make those analog signals travel over ethernet? As you can i dont have much knowledge about audio programming, so i would appreciate any help i could get on this mailing list. Thanks.