This is a trick to make iTunes sync much faster with your iPhone / iPad / iPod Touch by disabling the backup process of iTunes.
1. Find iTunesPrefs.xml in c:\Documents and Settings\UserName\Application Data\Apple Computer\iTunes. If you cannot find it, make sure you show all the hidden files in the folder as well.
2. Make a copy of iTunesPrefs.xml for backup in case you will need to restore it later when you do want a back up.
3. Open iTunesPref.xml with Notepad or WordPad text editor. Find the "User Preference" section and add the following right after the first <dict> tag
4. Save the iTunesPref.xml and restart your iTunes program.