OS 4.0 will do this by giving apps a limited collection of features they can perform when they aren’t the foreground app. Streaming audio services like Pandora, or VoIP ones like Skype to function in the background. Software will also be able to finish tasks this way, like uploading pictures or video to Facebook. Aside from these, most of the functions will stop. Unlike the current one, the next version of Apple’s OS will allow far more apps to perform functions in the background. Apple CEO Steve Jobs promises that this feature has been implemented in such a way that it won’t have a negative effect on the performance of the app running in the foreground, nor on the device’s battery life.Obviously, apps will have to be written to support Apple’s background APIs. The ones that don’t make use of these will completely close when the user switches away from them.Users will be able to switch between apps that are running by double-clicking the Home button to bring up a screen showing icons for currently running applications. Tapping on one of them will bring it to the fore.”Apple gave the world its first official look at iPhone OS 4.0 today, the next generation of its mobile operating system. This will include the feature most users of this company’s smartphones have been looking forward to for years: multitasking. It will also offer a range of other new features, like a unified email inbox, folders to organize application icons, a social network for gamers, and more.” Read more here: