According to TechWhack.com, Amazon has announced that they are now offering Warner Music Group music — including selections from Led Zeppelin and Metallica — on their Amazon MP3 music download service.

Amazon claims that their catalog of mainstream artists — which is free of digital rights management (DRM) software — is the biggest offering of its kind on the Internet. DRM-free music purchased from Amazon is compatible with almost any portable media player capable of playing MP3 files.

Apple iTunes is the largest digital media store on the web but a majority of the content offered is DRMed.