The store will feature millions of songs from 12,000 labels able to be played on a range of devices including iPods, Microsoft's Zune players and personal computers. Files will be offered in the standard MP3 format.
EMI Music is the latest to license its music catalog to the store.
Amazon did not say how much songs would cost or the terms on which it would offer music — per song, per album, by subscription or some combination of those plans. It also did not specify a date for the launch of the store.
The announcement comes as Apple hinted earlier this month at possible price hikes for songs on their iTunes service.
Apple CEO Steve Jobs opened the door to higher prices — as long as music companies let Apple Inc. sell their songs without technology designed to stop unauthorized copying.
Jobs contended that would by allowing consumers to play music they buy at Apple's iTunes store on any digital music player, not just the company's iPods.
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Although most of the major labels insist that safeguards are still needed to stave off online piracy and make other digital music business models work, EMI already struck a deal with Apple.
The record label agreed to let iTunes sell tracks without the copy-protection technology known as digital-rights management. The DRM-free tracks cost 30 cents more than copy-restricted versions of EMI songs and feature enhanced sound quality.
Apple and the recording companies declined official comment on their negotiations.
Four years ago, the majors bought into Jobs' one-price-fits-all vision and agreed to such licensing terms at a time online music services were failing to attract significant interest from music fans.