Multitasking is always at the top of the iPhone OS rumor list, though, so it may be premature to get too excited just yet. Tony Bradley is co-author of Unified Communications for Dummies .

Here's what multitasking looks like on iPhone 4.0. For full details on iPhone OS 4, and multitasking specifically, check out our definitive guides.

Apple has already introduced updates to its Mac OS X 10.6.3 operating system and the iPhone OS 3.2 SDK, meant for building mobile applications for the company's upcoming iPad tablet PC.