The app store was launched in July last year and allows iPhone and iPod Touch users to access third-party software. Apple said there are currently more than 85,000 apps available in 20 categories, including games, business, news, sports, health, reference and travel.
"The rate of App Store downloads continues to accelerate with users downloading a staggering two billion apps in just over a year, including more than half a billion apps this quarter alone," said Steve Jobs, Apple's CEO.
"The App Store has reinvented what you can do with a mobile handheld device, and our users are clearly loving it."
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See also: The 10 most stupid iPhone apps