Apple iOS 4 for iPhone: iOS 4 Review and Glitches - The biggest and most obvious update to iOS 4 is the ability for third-party applications to "multitask"—that is, you don't have to terminate them in order to do something else in another app. This is functionality that has been requested of Apple since the launch of the original iPhone in 2007, and it has been a long time coming. (Only the iPhone 4, iPhone 3GS, and third-gen iPod touch get multitasking.)

The software is being released today in advance of Thursday's 7 a.m. launch of the new iPhone 4. Apple's iOS 4 software promises 100 new features for owners of the iPhone 3GS, released last June, including the ability to multitask, or run more than one app at once. It also lets you take control of the growing inventory of apps by organizing them into folders.





-Make sure you are using the latest version of iTunes. Connect your iPhone to your computer.

-When iTunes opens, select your iPhone under Devices in the Source List on the left.

-In the iPhone Summary pane, click Check for Update.

-Click Download and Install. Do not disconnect your iPhone until the update has finished.