Apple has released iOS 5, the next generation operating system for iOS devices, to all iOS users as of today. The brand new OS is available now through iTunes software update and is compatible with the iPhone 3GS, iPhone 4 and iPhone 4S, the iPad and iPad 2, together with the third and fourth generation iPod touch. The company has also released OS X 10.7.2 which brings with it iCloud compatibility, as well as enhancements to other apps such as Safari and iCal for full iCloud functionality.
iOS 5 brings with it a massive amount of improvements and new features over iOS 4, all of which are demonstrated in full on the Apple iOS Features page. Some highlights include the new iMessage, Newsstand and Reminders apps, together with a new Notification Center, Wi-Fi syncing and activation, Twitter integration, and new iCloud based features such as Photostream.
The updates are both available now with iOS 5 coming through iTunes (probably the last time you are gonna have to do that) and OS X 10.7.2 through Software Update and they are both free of charge. Make sure that your devices are all synced prior to the backup so that you are able to restore all of your data. Also make sure that you have run Time Machine prior to the 10.7.2 update.