I'm wanting to sync too
I'm interested in this question to but maybe it's a little easier for me: I have two mac laptops (both sys X) and just would like to have my iTunes library be the same on both machines.
Reading somewhere else I learned about a program called RsyncX which seems to work well at copying the files, but the files don't show up (I guess somehow I have to update the iTunes library file?)
Anyway, any advice anyone has is appreciated.