Remove or find iPhone backup information

If you want to get rid of the backup information for an iPhone it's pretty simple. Open iTunes, then go to Edit->Preferences..., then click on the Devices tab. There you should see all devices you have synchronized with iTunes, along with the date of the most recent backup. To remove a backed up device, simply click on it to select it and then click on the Delete Backup button.

If you're curious where iTunes stores the backup files, I have the location of those as well. You have to unhide hidden files and folders in order to get there though. Go to My Computer->Tools->Folder Options, and then go to View and select Show hidden files and folders. Now, the location depends on your OS.

Windows XP

C:\Documents and Settings\USERNAME\Application Data\Apple Computer\MobileSync\Backup

Windows Vista

C:\Users\USERNAME\AppData\Roaming\MobileSync\Backup

You will see a folder that looks like a bunch of random characters or a GUID. That refers to your iPhone.