How to move an existing iTunes library to external drive for use by multiple computers?

You can do that, and you need to let iTunes manage your library, but be prepared for pain and suffering, especially if you ever start up iTunes without the network drive mounted. I have this setup (with an SMB share, though, so it's even less reliable) and it sorta works, but it's not ideal.

Bonus answer: Unlike earlier 802.11 formats, the speed does not drop down to the slowest connected device when non-n devices connect to the network. Before, 802.11g transmitters would slow down to b speeds if a single b device would connect. The n transmitters use two frequency bands, so it can maintain faster sppeds when a slow device connects. As Apple states, there is some degradation, but it's not absolute. Unless: you are in Great Britain, where the second frequency band is already in use. There, you will drop down to g speeds. As for the real question, I'm still looking for a good answer to this, for the same reason. There have been some recent posts to http://tuaw.com on this, but none have jumped out at me as the way to go. That's where I also read stories that detailed the speed answer I gave above.

Are you planning on pointing multiple Macs to the same die as their library? I think that isn't supported.

Thanks for the answers so far. @smackfu I don't understand your question. Is "die" a typo for "dir"? What I'd like to do is have a single library on the external drive, which will live wherever my router lives, and to point the desktop there *all* the time, and allow my laptops to access it whenever they're around. (Their local libraries would be "home base", so to speak.) The Lifehacker article that Matt points to shows great promise. I've got it bookmarked for this weekend when I try to set this up.

Cautionary notes: Backup the music on the harddrive. They will all fail eventually. You will lose data. If you follow the Lifehacker article (which is nice and how I have mine setup, although I run a mixed linux/windows network) remember to: 1. Use a consistent drive letter across your various computers. This makes it easier to get back up and running if the drive tanks and you have to replace it with the same (backed up, of course) data. 2. Backup your iTunes library (export) if you need to move computers.

I don't understand your question. Is "die" a typo for "dir"? Sorry, I broke my arm this weekend.... anyways, it sounds like your setup will work. Some people think they can use the share as the local library for all their computers, which doesn't work.

The lifehacker article says "This method only works with iTunes on Windows. Windows + Mac users: you're a different article." Does anyone have a link to that article?

I recently set up a USB drive connected to the Airport Extreme for a client of mine, and I learned a few things. First, if you're expecting to be blown away by the speed of this thing, think again. It's slow. Dog slow (and I was connected via ethernet!) For that reason, I might caution you against making this a primary drive for your media. It works fine and well for little transfers, but transfering 1GB seriously took an hour. For my setup, they just wanted a drive they could share files between, and some problems arose when they tried to save files (from Word) directly to the drive. These problems were solved eventually by changing the way the computers connected to the drive from AFP (Apple File Protocol) to SMB (Windows). Surprisingly, this also helped the speed issue a little, so that might be a good option to try out, if you run into trouble. You lose the built in automounting AFP gives you, but I figured out of a workaround. I disabled autodiscovery in the Airport Disk utility, and made an Applescript to mount the drive, saved it as an application, and made it a login item. tell application "Finder" open location "smb://[login]:[password]@[IP address]/[share name]" end tell A little legwork, but it worked like a charm. Hopefully this will help.

TUAW just posted http://www.tuaw.com/2007/03/02/tuaw-how-to-use-your-itunes-library-over-airport-disk/ on moving your library over to an Airport Extreme disk.