When I choose to install a new version of iOS on my device via iTunes, the installation file is huge (e.g. 750 MB). Where does iTunes save this file, and does it get deleted after the installation is done?
On Windows XP
Documents and Settings\<User>\Application Data\Apple Computer\iTunes\iPhone Software Updates
On Windows Vista/Windows 7
Users\<User>\AppData\Roaming\Apple Computer\iTunes\iPhone Software Updates
~/Library/iTunes/iPhone Software Updates
I believe that the updates do not delete after they are installed.
On Mac, you can delete the iOS firmware by going to Finder, pressing ⌘ cmd + ⇧ shift + G and go to
~/Library/iTunes/iPhone Software Updates. From there, you can delete the files.
You don't have to delete them unless you are short on disk space, as they get replaced by newly downloaded files whenever there is an upgrade.