iPhone apps will work out of the box on Apple's new iPad, according to Apple VP Scott Forstall. iPhone apps can run in two modes, one in their native resolution in the middle of the iPad's screen (surrounded by black), or in a double pixel mode for running full-screen. A third option allows developers to make adjustments to their iPhone apps that will allow them to run natively in full-screen mode when on the iPad.

At Apple's media event unveiling the new device, Engadget reported Mr. Forstall as saying, "So all of the iPhone apps will run on this. In fact when you buy it, download all the apps you have right onto the iPad. Now if the developer spends some time modifying their app, they can take full advantage of this display."

Mr. Forstall also noted that Apple did rewrite its own apps for the iPad, meaning that Mail, Safari, Address Book, and the other Apple apps that will ship on the device have all been specifically crafted to take the limitations and enhancements that the iPad offers.

For developers, Apple said it was releasing a new version of the iPhone SDK that would allow developers to modify their apps for the iPad today.