Apple has approved Opera Software's mobile internet browser for use on the iPhone.
The move makes Norway's Opera browser the first to rival Apple's own browser software in the App Store.
Opera has led the fight in Europe to break Microsoft's browser monopoly through bundling Internet Explorer with its Windows operating system.
The firm applied in March for its mobile browser to be distributed on iPhone, but Apple has taken three times as long as usual to give the go-ahead, according to US reports.
Analysts said the decision was difficult for Apple as its internet browsing function is key to the success of the iPhone.
But Opera's mobile browser promises up to six times faster download speeds than Apple's own browser and to reduce data traffic by up to 90%.