Napster has launched the world’s biggest DRM-free MP3 download store with a catalog of more than 6 million songs. Most of the songs available on the store sell for $0.99 each, with most albums selling for $9.95. “We’re now moving from under the DRM cloud,” said Chris Gorog, Napster chief executive. “Now consumers can use Napster with any device.” The move makes Napster the latest high-profile DRM-free music download…