No No No
It's at the moment only available in the LimeWire betas but it works with any computer. Mac OS X, Windows and Linux are tested so far but it should also work with Solaris, *BSD and all the other Java 1.4 compatible systems.
Since iTunes is only available for Mac and Windows you need at least one of these two systems to access the shared library but the library could run on -- lemme see - a HP-UX box (hope it's exotic enough
)