I don't know if this is the right forum, but here's a hint:
if you enter this into the Terminal.app (Mac OS X Utility), iTunes can't update to 1.1.3:
chmod 400 ~/Library/iTunes/iPhone\ Software\ Updates/
if you want to go back to normale state use this command:
chmod 755 ~/Library/iTunes/iPhone\ Software\ Updates/
this is not the same as unchecking the option in iTunes to "check automatically for updates" - as this just let's iTunes check itself for an update, but not the iPhone - it's something totally different!
found on http://www.macbug.de