Yep, John is right, you need to move the content on the PC. You can use software to copy the ipod to a new machine.
You can however copy the backups across and re sync to make sure all content is copied properly from one machine to the next.
First, sync with your old machine to make backups up to date.
The manual way to do it, is to copy Documents and SettingsusernameMy DocumentsMy MusiciTunes. (the whole contents of the folder) on the old machine to the same location on the new machine. (In vista it will be usernameMusiciTunes or in 7 it will be usernameMy MusiciTunes).
Once that is done, you need to find the backup location. This is stored in C

ocuments and SettingsusernameApplication DataApple ComputerMobile SyncBackup for XP or C:UsersusernameAppDataRoamingApple ComputerMobileSyncBackup for vista/7. Copy all the folders you find, copy them to your new laptop in the new location.
When you plug in your ipod/ipad in it will ask you to format it for use with this machine, but when you restore from backup your previous backups will be in the list.