In July, at MacWorld Expo New York 2002, Steve Jobs demonstrated a beta version of iTunes which incorporated Rendezvous technology, allowing dynamic addition and removal of music libraries from computers within Rendezvous' reach.
At that time, the technology was slated for early 2003. As expected, we've heard that iTunes (version 4?) will contain this expected technology, and is tentatively slated for MacWorld SF 2003.
Other new features to come with the next revision to iTunes will also be "smart" visualizations, and long-awaited MPEG4 AAC codec support.