Less than a week after releasing the iPad digital tablet, Steve Jobs and Apple today announced the first details of version 4.0 of the iPhone mobile device operating system. Seven major features were unveiled, including application multitasking, a unified in-box for e-mail, and a new mobile ad platform, iAd.

Perhaps the most anticipated feature announced was multitasking. According to Jobs, Apple has implemented this ability without impacting the performance or battery life of the iPhone. Once developers build it into their apps, features like background music and phone calls using voice over Internet protocol will be enabled on the iPhone.

While many features of the new operating system will work on any iPhone some, like multitasking, will require a 3Gs or 3rd-generation iPod touch. The iPhone version of the OS is expected this summer, with a version for the iPad arriving in the fall.

>Live from Apple's iPhone OS 4 event! (Engadget)