It seems like protocol is pretty much deciphered (for forensic purpose, more likely.) I never heard any existence of it outside of Windows.
I've once tried to run it on Wine while ago, it looks like it incorporates quite a bit of environment checking (so to prevent someone from modifying network parameters?) and I remember it was having problems running -- not sure if it's still the case with later version of Wine.
The only other down-side I can see off the bat is that it runs only on Windows machines.
http://en.wikipedia.org/wiki/Share_(P2P)
Anyone aware of an OSX version?