Facing intense competition from phone makers wedded to Google's Android software, Steven P. Jobs, Apple's chief executive, finally plans to make the iPhone available on Verizon Wireless, the largest wireless carrier in the United States. After more than three years of using only AT&T cell phone networks, Apple is now making a version of the iPhone 4 for Verizon's network, according to a person who is in direct contact with Apple. Apple and Verizon will begin selling the phone early next year, said the person, who agreed to speak on the condition of anonymity because the plans were supposed to be confidential and he did not want to alienate his contacts at Apple. Apple and Verizon Wireless declined to comment. The arrival of the iPhone on Verizon, which has long been expected and frequently rumored, could sharply alter the dynamics of the U.S. smart phone market. The iPhone remains the best-selling smart phone. But around the world, many carriers, especially those that do not have access to the iPhone, have been promoting an array of models running on Android software. Collectively, those phones now outsell the iPhone. The Android's rapid ascent threatens to blunt Apple's lead in the market for high-end smart phones. No other Apple product brings as much revenue for the company as the iPhone, and analysts say that seeing that lucrative market imperiled may have finally pushed Apple into ending its exclusivity with AT&T. A Verizon iPhone could quickly tilt the marketplace back in Apple's favor. For all its success, the iPhone on AT&T has been plagued by complaints of poor network coverage, especially in some major cities like New York and San Francisco. Many potential customers have chosen to buy Android handsets to avoid problems with dropped calls and dead zones. But many surveys show that many owners of Android handsets would buy an iPhone if it were available on Verizon. At the same time, AT&T iPhone customers may switch to Verizon as their contracts expire, even though they would have to buy a new phone. Apple's AT&T phone, which uses GSM networking technology, would not work on Verizon's network, which uses a different networking technology called CDMA. Another factor that could be pushing Apple to end its AT&T exclusivity is the impending arrival of phones running Microsoft's new Windows Phone 7 software. The two companies are making a joint announcement about its phones Monday. Early reviews of the devices have been positive, and Microsoft, which has faltered repeatedly in the phone business, plans to spend heavily to market the new handsets. 