I should add that I have a month old backup of my music files and iTunes library. I used the backed up "iTunes Music Library.xml" file to help restore my playlists - but it didn't help with the iPhone sync settings. Can I use something from the backup to set things straight?

Sorry if this has been answered before. I couldn't find such a post, though. My iTunes 10.1 library mysteriously went blank the other day (all playlists and podcast subscriptions gone). Luckily, the files were still on my Mac, so I was able to get things back to how they used to be (almost)...