Apple has announced that one billion songs have been legally downloaded from the iTunes Music Store since it was launched less than three years ago.

The billionth song Speed of Sound was purchased as part of Coldplay’s X&Y album by Alex Ostrovsky from West Bloomfield, Michigan. He will receive a 20-inch iMac, 10 fifth generation iPods and a $10,000 gift card good for any item on the iTunes Music Store. In addition, Apple will establish a scholarship to the world-renowned Juilliard School of Music in his name to commemorate this milestone.

“I hope that every customer, artist and music company executive takes a moment today to reflect on what we’ve achieved together during the past three years,” said Steve Jobs, Apple’s CEO. “Over one billion songs have now been legally purchased and downloaded around the globe, representing a major force against music piracy and the future of music distribution as we move from CDs to the Internet.”

Hype or not, Apple’s milestone demonstrates both the increasing importance of digital downloads to the world of music, and the domination the company has achieved of this market.