Audio Stream and Sync to multiple devices

Hi,

I've got a house with computers and good speakers in many of the rooms, and iPods and docks and speakers in others, what I'd like to do is start playing some music from one of these devices and have it sync up with several others (ie, playing on my macbook, but streaming it over Wi-Fi to 2 other computers in different rooms and an iPod Touch).

What I'd like to do is be able to walk around the house and have the same music playing, in sync, with all computers and devices. Helpful for cleaning days or parties etc where there's lots of rooms, but only one set of speakers hooked up to the music computer.

Any help would be really appreciated. I know you can stream to Apple TV from iTunes or an iPhone, but I don't think that I should have to fork out $100 per room on an apple TV, then go to the hassle of hooking them up with the current devices just to be able to have the software that'll let me sync up my music throughout the house.

Thanks again

Leaping..