Info from MAC WORLD:
Using Multiple iPOD on one computer: By default iTunes is set to automatically update all songs and playlist. If you want manual control or if you are connecting an iPOD that is synced with one computer to another system and don`t want to overwriteall the music on it, you will to switch to manual mode.
- Conect the iPOD
- click on the button when asked to link your iPOD with current libraray.
- click on iPOD icon on the iTune window and select manually manage songs and playlist.
It is possible different users to maintain iTunes under their login, however since iTunes store music under each users home folder, it will create duplicate copy of shared songs. To avoid duplicate each user can consider setting iTunes to store music to a different location on the same computer or to another networked computer. To relocate the folder, find its current location at the general tab of iTunes, advanced preference pane. Quit iTunes and move/copy the iTune music folder you just found to a new location. Now open your iTune/edit/preference/advanced/click on change and pointed to your current folder. Repeat the process for all users.
If you do not have mutiple users account there are another solution: example create multiple iTune library.
When connecting an iPOD to more than one computer, you may want to have the same music on all computers.
iPOD on Network computers: Synchronizing iTunes can creat to much work, and using the free software called syncOtunes 0.95 will help. After installing the software:
1. Select your local iTunes Music Library.xml file, and then select the same music on remote computer across the network, and then click on compare files and click on copy