I keep all my MP3 files on a Windows machine that houses a 120GB drive. With the release of iTunes4, I wanted to try out the Rendezvous sharing. So I added them to the library (with iTunes NOT copying locally), and all was good. The biq question was what would happen when I didn't have the PC drive mounted?
The iTunes mounts it automatically! That's right. I go to play a song in the library and I get prompted to authenticate. I imagine if I stored this in my keychain I wouldn't even get that. Neat little trick. May have been in iTunes3 and older, but I never tried. Just thought I'd share my experience.
[robg adds: I believe this is a feature of the file manager more than iTunes itself, but I may be wrong...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030429130115492