"We are going to take the biggest leap since the original iPhone," Jobs said in a keynote speech at Apple's Worldwide Developers Conference (WWDC) at San Fransisco.
Jobs said the iPhone 4 includes more than 100 new features including a front-facing video camera to allow for video-conferencing, a better still camera, improved battery life and a screen with higher resolution.
"There has never been a display like this on a phone," Jobs said.
The 3.5-inch screen is the same size as on previous models but features 326 pixels per inch, four times more pixels than the earlier iPhones.
"There is a magic number around 300 pixels per inch that is the limit of the human retina," Jobs said. "We are over that limit."
"That's going to set the standard for display for years to come," he said.
The improved battery allows for 40 percent more talk time, Jobs said.
He also said the iPhone is 24 percent thinner than the previous model, iPhone 3GS.
"It is really thin," Jobs. "It is one of the most beautiful designs you've ever seen. Its closest kin is a beautiful old Leica camera."
The Apple chief executive also joked that some of the attendees may have seen the phone previously "because there are have been a few photos around."
Technology blog Gizmodo obtained a prototype of the phone in April from a 21-year-old man who found it in a California beer garden, where it had been lost by an Apple software engineer.
