writes "Apple has issued an update to iTunes 4, iTunes 4.0.1. It can be downloaded via Software Update. The big change seems to be that iTunes will now only stream music to other Macs on the same subnet. This is presumably a response to people publishing public lists of shared iTunes playlists, though it does mean that anyone wanting to stream music from home to work or vice versa is SOL. Oh well."
You can't share between 4.0 and 4.0.1 iTunes, so be careful in updating. AppleScript access to shared playlist tracks is fixed, though. Woop woop.