San Francisco  - Owners of Apple's popular iPhones have downloaded over 1 billion applications for the must-have smartphones, Apple said Friday.

The landmark download was reached just nine months after Apple launched the App Store which allows users of the iPhone to download new programs for their devices. The program has proved so popular that thousands of companies and individuals are believed to be writing applications for the phone, which Apple then distributes via the online marketplace.

According to Apple over 35,000 separate applications, many of them free, are currently available over the online marketplace.

"The revolutionary App Store has been a phenomenal hit with iPhone and iPod touch users around the world, and we'd like to thank our customers and developers for helping us achieve the astonishing milestone of one billion apps downloaded," said Apple executive Philip Schiller. "In nine months, the App Store has completely revolutionized the mobile industry and this is only the beginning."

The announcement coincided with reports of disappointing sales for one of the iPhone's most highly touted competitors in the US.

T-Mobile USA announced that it has sold 1 million units of the G-1 device - the first smartphone to run Google's Android operating system. The phone took six months to reach that sales point. In contrast, the Apple's iPhone 3G sold 1 million units on its launch weekend.(dpa)