There are also big improvements to email and other features designed to make Apple's mobile devices better tools for business users.

The new operating system is compatible with the iPad and newer versions of the iPhone and Touch. But it appears that older versions of the devices won't support it. Users of the iPhone 3GS and the Touch can download the software this summer; iPad users in the fall.

The new operating system, set to ship this summer, lets multiple applications run at the same time and gives the user quick access to them via a dock at the bottom of the screen. The current version of the operating system creates headaches for developers because applications can't send or receive information unless they are active. That's no longer the case.

One big advantage is the ability to move from one app to another without losing your place in either application, a real problem when using today's task switching function.