I have a scheme in mind to get around the DRM-constrained design "flaws" in iTunes for a multi-user family.
The first step is to create a shared folder that's read-only for most of the family. That's where the iTunes music files will live. Problem is, that's not easy to do in OS X. As near as I can tell this 2001 article is still true today: The Mac Observer: Hot Cocoa - Unlocking The Power Of Groups In Mac OS X. I think there are some more GUI utilities one can buy (ex: Sharepoints), but Apple has not addressed this -- probably because this is the province of OS X server. Mac Classic was far more useful as a home file server.
Microsoft did the same yucky thing; in many ways Windows 95 was a better fileshare than Windows XP Pro. In this case, though, Apple is even worse than Microsoft.
Anyway, getting the file share working is the least of my concerns! I can do the command line stuff or use sharepoints. This will be interesting ...
Update 2/27/08: I put my iTunes Library in my Public folder, which grants read access to everyone, but no write access. The Shared folder grants read and write access to everyone. That seemed to work, but I discovered that iTunes actually uses a mixed model to store metadata. Some is stored in the internal database, some stored in the local file system. It's complex, I think there are some significant deep design problems with this in iTunes. I need to experiment with granting write access to one user but not the children. Looks like I'll be donating money to Sharepoints if it works!