Apple Inc. (AAPL) Monday said the battery of its widely anticipated music-playing iPhone will last longer than expected, sending its shares higher.

Apple said the iPhone would provide up to eight hours of mobile phone talk time, or six hours of Internet use, compared with its previous expectation for five hours of talk time issued in January.

Apple said the top surface of the touch-screen phone, due to ship on June 29 and priced at about $500 to $600, has also been upgraded to optical-quality glass from plastic, making it more resistant to scratches.

AT&T Inc. (T), the biggest U.S. wireless provider, has an exclusive agreement to sell the phone in the United States for at least two years. It has said that more than a million people had sent the company e-mails inquiring about the phone.

Apple shares rose $3.02, or 2.5 percent, to $123.50 on Nasdaq after the news. AT&T shares rose 26 cents to $40.54 on the New York Stock Exchange.

Manufacturers are battling to increase the battery life of cell phones, as constant communication with radio broadcast towers tends to drain power more quickly than unconnected consumer electronics devices.

Smart phones like the iPhone also need lots of power as they aim to handle Web browsing, personal data storage and music and video playback -- as well as talk.

Apple said its battery claims are dependent upon specific configurations and "many other factors." It did not elaborate.

In comparison to Apple's eight hours of talk time, one rival music player phone from Samsung Electronics Co. Ltd , the Upstage, has a battery life of up to 6.3 hours, according to Sprint Nextel Corp. (S), which sells the phone.

The BlackJack, another Samsung phone has talk time of up to 5 1/2 hours, according to AT&T, which sells the phone.

Apple said its device can support seven hours of video playback or 24 hours of audio playback and more than 10 days of standby time.

While the Curve from Research In Motion has a talk-time of up to four hours, it has standby power of up to 17 days, according to AT&T's Web site.