syncOtunes seem like a great way to sync the libraries of multiple machines. It copies the files across to another machine and imports them to your second iTunes library. I have not played with it yet, but would actually prefer to see a system that simply synced the library file itself, leaving the tunes in one place. In my config I use multiple machines and essentially the same library file, which lets me mount the network drive and play anything I want. I manually sync my iPod so I can copy to it from any machine as well.