It's a pretty trollish question, but I'll give you the benefit of the doubt :) The iPhone runs OSX, so mutitasking's built in at an OS level. For a number of r

It's a pretty trollish question, but I'll give you the benefit of the doubt :) The iPhone runs OSX, so mutitasking's built in at an OS level. For a number of reasons Apple have decided that user-installed apps can't run in the background, meaning that when you select another app, the previous one actually closes. Some Apple apps, like the phone, iPod player etc are exempt from this rule and do run in the background.