Capping a day of dueling announcements from rival cellphone service providers, AT&T said Tuesday that it would allow users of Apple Inc.'s popular iPhone to make Internet telephone calls over its wireless network.
Hours earlier, Verizon Wireless, the nation's largest mobile carrier, said it was teaming up with Internet search giant Google Inc. to release a family of cellular devices powered by Google's Android software, whose capacity to run a vast array of "apps" is widely thought to represent a threat to the iPhone.
Verizon said the new phones also would support Google Voice, a much-anticipated application that lets users create a single phone number that works with all of their telephone lines and cellular devices.
Both announcements amounted to the providers' relinquishing some control over the kinds of programs that could be run on the increasingly smart and powerful devices they provide.
In the case of AT&T, allowing Internet telephony applications such as Skype could help users avoid exhausting their allotment of monthly minutes and incurring costly overage fees.
For Verizon, allowing users to install any of Android's more than 10,000 apps -- none of which have to be pre-approved by Google -- means it opens itself up to phone functions it could not possibly anticipate.
"You either have an open device or not," Verizon Wireless Chief Executive Lowell McAdam told analysts, "and this will be open."
Apple's iPhone and iPod Touch are not open, requiring any app to go through an often lengthy approval process before it is made available to device owners through the company's App Store.
Still, the company has sold more than 50 million of those devices, and users have downloaded 2 billion apps, leaving Google, its main rival in the online app market, far behind.
"The Android marketplace doesn't have anywhere near the momentum or the oomph of marketing muscle that Apple has," said Charles Golvin, an analyst with Forrester Research. "On the other hand, you have the benefit of [Android's] openness and an expanding level of innovation because of the number of parties at the table."
Although Apple has only one phone, the number of Android-powered devices has grown from just one last year to 11 that are out or have been announced. T-Mobile already offers Android devices, and Sprint will launch one later this year.
The partnership between Google and Verizon comes as the fight for dominance in the mobile smart phone market grows increasingly contentious.
During a Monday night football game this week, a Verizon commercial claimed the company covered five times the area of AT&T's mobile network, and called its competitor's coverage "spotty."
On the technology side, a spat between Google and Apple has escalated in recent weeks over Apple's refusal to approve Google Voice for its App store. When the Federal Communications Commission inquired about the decision, Apple replied that Google Voice altered the iPhone's user experience by "replacing the iPhone's core mobile telephone functionality."
Apple's explanation stood in contrast to AT&T's decision to let its customers use iPhone applications that would bypass its own telephone network.
But Apple said it was happy about AT&T's policy change, and welcomed so-called Voice over Internet Protocol (or VoIP) applications.
"We will be amending our developer agreements to get VoIP apps on the App Store and in customers' hands as soon as possible," the company said in a statement.
Apple declined to say whether Google Voice would be available in its App Store as a result of the change.