Amazon.com has launched a public beta of its new ' Amazon MP3' service. It's a new digital music download store which Amazon says has the biggest selection of a la carte DRM-free MP3 music downloads.

Amazon MP3 has over 2 million songs from more than 180,000 artists represented by over 20,000 major and independent record labels. It's designed to sit alongside Amazon.com's existing selection of over 1 million CDs to now offer customers "more selection of physical and digital music than any other retailer".

Amazon to rival iTunes

"Amazon MP3 is an all-MP3, DRM-free catalogue of a la carte music from major labels and independent labels, playable on any device, in high-quality audio, at low prices," said Bill Carr, Amazon.com Vice President for Digital Music.

"This new digital music service has already been through an extensive private beta, and today we're excited to offer it to our customers as a fully functional public beta. We look forward to receiving feedback from our customers and using their input to refine the service."

Every song and album on Amazon MP3 is available exclusively in the MP3 format without digital rights management (DRM) software. This means that Amazon MP3 customers are free to enjoy their music downloads using any hardware device, including PCs, Macs, Apple iPods, Microsoft Zunes, Creative Zens and SanDisk Sansas.

Every song on Amazon MP3 is encoded at 256 kilobits per second, which gives customers high audio quality at a manageable file size. There are, however, no plans to introduce the service to the UK in the near future.