What is IPSW?
Very simple question. Unfortunately many people are still looking at it as this term is used frequently in the iPhone discussions and iPhone lingo. IPSW simply means iPhone Software.
For a normal IPSW with AT&T subscription, the process of downloading the software is simple and straightforward, at least from the user perspective. You search for an application download it on your iPhone and you are done. The Application may be paid or free one.
You can also connect the iPhone to iTunes which may prompt you to upgrade the firmware ( iPhone baseband or the iOS) version.
In any case IPSW means iPhone Software. Hope you got the point.