New Apple iPhones

. Apple has stumbled before in its foray into the cellular business, with a poorly executed price cut two months after the iPhone launch that left many early buyers fuming. And now that it's a significant part of the wireless market, Apple faces some of the same threats as more-established handset makers.Among those pressures: intensifying competition and the uncertainty of a fractured market with many big players. There's also the risk that even with Apple's sparkling reputation, theApple iPhone might become so widely available that it loses some of the cachet that inspires buyers to wait in lines outside stores. It's clear that Apple has rattled the cellphone industry with the iPhone's design and features, which are being copied by other handset makers. And the company appears on track to meeting its sales targets for the iPhone — essential to appeasing investor