When it goes on sale in the US on June 29, the iPhone will enable as many as 8 hours of talk time or 6 hours of Internet use, Apple said. Previously, the company said it would provide only 5 hours of talk time, when it first announced the product in early January.

When it retails, the iPhone may also give users up to 24 hours of music or 7 hours of video playback. Previously, Apple said it would give just 16 hours of music playback.

Apple also said yesterday the surface of the touch-screen device would not be made with plastic but instead with optical-quality glass to make it more resistant to scratches.

The iPhone is slated to hit European retail shelves in the fourth quarter.

In the US, it will cost $499 for a 4GB model or $599 for an 8GB, which includes a two-year contract with Apple’s exclusive US provider Cingular Wireless, now a unit of AT&T.

Our View

Giving the iPhone more staying power is a step in the right direction, but it likely won’t be enough to lure enterprise users.

Eight hours talk time is more than some other smartphones, such as Samsung’s BlackJack smartphone, which promises 5.5 hours of talk time, according to reseller AT&T. But the iPhone’s battery is reportedly not as easy to remove as rival devices.

And while its touch screen helps make the device look gorgeous and so easy to use, even Apple chief executive Steve Jobs struggled somewhat to tap out a text message via the on-screen keyboard, when he first announced the phone earlier this year. For now, it seems for typing buttons are faster and easier. And at $500 a phone, it’s possible that only top execs – and prosumers, of course – will be running to their Apple store at the end of the month.