Internet’s largest retailer, Amazon has finally launched a public beta of its much-anticipated and full fledged online music store. Almost four months following its announcement back in May, the newly launched fully functional public beta music store, called “Amazon MP3” offers customers (Digital Rights Management) DRM-free MP3 music downloads, without copy protection.

With a library of more than 2 million songs, 180,000 artists represented by 20,000 major and independent labels, Amazon MP3 is the latest attempt by Amazon to expand its existing selection of more than 1 million CDs to music lovers who prefer unfettered music downloads.

Following Apple’s recent lead in selling DRM-free music downloads, Amazon said that more than 2 million of its songs are priced from 89 cents to 99 cents.

While the top 100 best-selling songs are 89 cents, most albums are priced from $5.99 to $9.99, the top 100 best-selling albums are $8.99 or less, Amazon said.

Amazon MP3’s customers will be able to take pleasure in their music downloads using any hardware device, including PCs, Macs, iPods, Zunes, Zens, iPhones, RAZRs, and BlackBerrys, the online retailer said.

Amazon’s MP3 format music downloads are encoded at 256 Kps (kilobits per second), which promises its users higher audio quality, and fairly sized file download.

Like any other items sold on its website, Amazon MP3 allows customers to purchase their music using Amazon’s existing shopping cart.

The online retailer is also offering its customers a desktop tool, called “Amazon MP3 Downloader”, which lets its users add their MP3s to iTunes or Windows Media Player libraries.