Apple CEO Steve Jobs said Tuesday that it's his company's job to stymie hackers who try to unlock the iPhone -- the first time the company has officially said it would fight attempts to use the popular device on unauthorized networks.

At a London Apple retail store where he announced the iPhone's Nov. 9 U.K. debut, Jobs responded to a question about whether Apple would put a stop to the unlocking hacks that have mushroomed recently. "It's a cat-and-mouse game," said Jobs. "We try to stay ahead. People will try to break in, and it's our job to stop them breaking in."

In last few weeks, people have unveiled several unlock hacks that let users swap the iPhone's included SIM card with one from another cellular service provider so the phone can make calls on that carrier's network. With the iPhone limited to domestic sales until November, unlocking is the only way consumers living outside the U.S. have been able to use their phones.

Last week, the iPhone Dev Team posted a free unlocking hack, then followed it Monday with anySIM, an unlocking tool tucked into a graphical interface. Just a day before the iPhone Dev Team released its free hack, a group called iPhoneSIMFree began selling an unlocking tool of its own through a network of online resellers at prices ranging from $45 to $99.

Carolina Milanesi, a Gartner analyst who was at the London presentation, said she wondered if it matters much in the long run whether Apple stays a step ahead of hackers, as Jobs said it must do. "At the moment, as a consumer, you need to be very careful about unlocking the iPhone, and know how you want to use it," she said. "If you unlock it, you are not going to have a flat rate, and you will not have access to the 7,500 hot spots."

O2 Ltd., the iPhone's sole carrier in the U.K., will offer three flat-rate plans -- dubbed "tariffs" in Britain -- that range in price from $70 to $110 per month. Flat-rate plans are relatively rare in the U.K., said Milanesi. "If you unlock and then use the Internet and e-mail, you may be surprised by your first bill," she added, referring to the pay-as-you-go data rates charged by most carriers in the country and elsewhere in Europe.

O2 has struck a deal with a Wi-Fi provider called The Cloud that will give iPhone users unlimited wireless access to some 7,500 hot spots in Great Britain and Northern Ireland.

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