Where are iPod touch backup file?

it's a good question. i'm not exactly sure. you should definitely transfer your itunes library file from your music folder.

Don't know where it backups specfic files but I would definitely backup all folders under
My Computer just to be safe. You many also want to check Microsoft site to see if they recommend any other files critical to XP itself.

It's located at:
C:\Documents and Settings\<username>\Application Data\Apple Computer\MobileSync\Backup.

Note that the backup file _does not_ contain iTunes media content (music, apps, videos, etc.), or the photos synced to the IPT. The backup contains settings, 3rd party app data (not the apps themselves), Camera Roll photos, etc. So, you need to back up your iTunes Library as well.

You may need to turn viewing of hidden files. In a Windows Explorer window, Tools menu > Folder Options > View tab > click the radio button to 'Show hidden files and folders' then click Apply to All Folders.

Where are the backup files on a Mac?

~/Library/Applications Support/MobileSync/Backup

Thank you for that info. Do you know if it's OK to delete all but the most recent backup? Apparently I have 623 backup files in that folder. Geeze!)

Apparently I have 623 backup files in that folder.

Are you sure of that? How many folders show up at the top level of the folder 'Backup'? These will be folders with unique IDs for names (i.e. long hexadecimal strings). Each folder is a backup. Inside each folder are many files (hundreds or thousands) that are all part of that backup.

iTunes only keeps one backup, unless you interrupt a backup (leaving a damaged one) or manually create one in iTunes (secondary-click device and select Backup). So, for example in my Backup folder there are three subfolders - one for each iPhone (two syncing to this computer) and one for an iPod Touch. This can be confirmed in iTunes > Preferences > Devices tab, which lists the three backups by device name and date (and the dates match the modified dates on the folders).

If you really have 623 backups (i.e. you have 623 folders in the Backup folder and 623 backups show up in iTunes Preferences), you have something very odd occurring.