How to Sync iPod with Multiple Computersby Contributor
If a friend gives you an iPod that was synced with his or her computer and you want to keep all the cool tunes on the iPod, don't worry. You can sync an iPod with multiple computers.
Download iTunes onto your computer. Connect the iPod to your computer. A warning comes up that says "This iPod is synced with another computer. Do you want to sync the iPod with this computer? All data will be lost." You have the options of clicking "OK" or "Cancel." Click Cancel.
Select your iPod in the "Devices" section of the iTunes left navigation panel. In the main iTunes browser window, select the "Summary" tab. Check the "Manually manage music and videos" option. This deselects the automatic sync settings for the Music, Movies, and TV Shows tabs. Automatic syncing for Podcasts, Photos, Contacts, and Games can be individually disabled by selecting each of those tabs. Click Apply.
To manually add music, audiobooks, movies or TV shows to your iPod, choose one of these categories under "Library" in the left navigation panel. Select the items you want. Drag and drop them onto your iPod icon listing under "Devices. To add an entire playlist, select it in the navigation panel and drag it onto your iPod in the same manner as an individual song. When you are ready to disconnect the iPod, select it under "Devices" and click the eject icon.
With manual managing enabled, the iPod becomes like any other USB device. Thus, the iPod must be manually ejected in iTunes before disconnecting.