When you try to sync your Ipod or Iphone to a second computer using Itunes, it show this warning
“The iPod\iphone is synced with another iTunes library. Do you want to erase this iPod and sync with this iTunes library?”
Remember that an iPod or Iphone can be synced with only one iTunes library at a time. Erasing and syncing replaces the contents of this iPod or Iphone with the contents of the iTunes library on the local computer.
Here are some steps that can be follow, to not delete the data on the Ipod or Iphone: Wiki Answer
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