PulseAudio can seamlessly play audio on any networked PC, regardless of what computer youre actually at.
Read it here
This fall, I did a presentation for OSU Open Source club on the PulseAudio sound server, a replacement for ESD with a lot of cool additions and tricks. Unfortunately, I couldnt get it to work back then, nor could I until I upgraded to Feisty Fawn. However, I finally figured out how to do it.