So multitasking is finally coming to (some) iPhones, iPod touches, and the iPad. This gives the user the ability to switch between applications without having to close one app in order to open another.

How it works

It will be as simple as double-clicking the home button on your device which will open a tray showing all running applications. Similar to the function you’re used to on your Mac (cmd + tab) and PC (alt + tab). So an example would be tapping a link within and email in Mail. Traditionally this would close Mail and launch the webpage within Safari. In the new OS, Mail would not close, but Safari would still open, allowing you to switch back to Mail when you’re done with Safari.

Apple also claims this will not deplete battery life or bog down your device. This is achieved by not giving all system resources available to every application that is open (which is how multi-tasking typically works). Instead, only the following specific actions are capable of doing this: background audio, voice over IP, background location, push notifications, local notifications, task completion, fast app switching.

Who can use it?

If you’re running on an iPhone 3GS or a 3rd Gen iPod Touch, then you’ll be able to enjoy this new feature of the OS. However original iPhone, iPhone 3G, and previous generation iPod Touch users will not get to use multitasking. This is not a shocker for original iPhone devices, but as the 3G is still on sale and one of the most popular of the devices, this is a bummer. The iPad will see this new OS and multitasking this Fall, while everyone else can see it this summer.