Why not use Raspbmc or Open elec. Raspbmc available here http://www.raspbmc.com/
not too sure about the link for Open Elec.
Not only would this give you streaming audio but you would also have the option of video as well if you wanted it.
There is also an app for your smartphone to act as a remote control for the XBMC.
I actually have a PC running Ubuntu 12.1 and the Eden version of XBMC with my media stored on a NAS. Works very well. I have also used a PI running Raspbmc and this works as well. the GUI is a bit slow compared to the PC version (mind you the PC version does have an SSD instead of a normal hard drive and a quad core processor and 1GB graphics card and 4GB of memory, so not a fair comparison).
Its also possible to use a single database for multiple XBMC units, just go over to the forums on www.xbmc.org
to find out how its done.