When there are multiple iPhones in a household and you want to upgrade them all from a single iOS download via multiple Macs, it can be a bit of a challenge. I have previously blogged about how to do this. This post contains the link to the new major version (5.0) of iOS for the iPhone 4 which contains over 200 new features.
Download URL
The iOS 5.0 firmware update file (.ipsw) is available at:
Update
Updating each iPhone as per my previous post resulted in a strange 3002 error.
I finally managed to solve this by placing the downloaded .ipsw file in the following location on each Mac:
/Library/iTunes/iPhone Software Updates
Create the folder if it does not exist. Clicking on the update button in the iPhone Summary page in iTunes will update your iPhone. Repeat with each Mac and iPhone combination.