In a direct challenge to Apple’s dominant iTunes store as well as Amazon’s steady growing MP3 download service, Napster has opted to switch to DRM-free MP3s for their entire six million song library. Napster claims its store is 50% larger than any other MP3 store and touts the largest major label catalog in the industry, as well as the largest library of independent music available anywhere.

Keeping with the industry standard, individual songs cost 99 cents apiece, while most full albums go for $9.95. Songs are encoded at a high-quality 256 kbps bit rate, and include high-resolution album art. It’s interesting to see how more and more stores are making their push into DRM-free sales, though it is going to take much more than that and an ample catalog to challenge Apple’s dominance, which stems from the fact that its store is tightly integrated with the most popular portable media player on the market.