Although Apple has not yet officially stated the time when iOS 6 will be released today, unconfirmed reports have claimed that it will become available at 1:00pm ET, or 10:00am PT.
As the update will be a significant change to iOS devices, with the risk of installation-related issues, we would strongly recommend that you take the time now to back up any devices that will be receiving the update. iTunes and over-the-air update options will likely be available.
