It seems that the recent trend in the music industry has been to make tracks available without DRM but to snub Apple by refusing to allow them to sell the DRM-free tracks through the iTunes Music Store. I suspect that this is a sort of vigilante antitrust action by the record companies that they hope will enable them to recapture a bit of power relative to Apple.
Currently, there are a lot more DRM-free MP3s available for download through Amazon.com than there are through iTunes Music Store, and Sony’s catalog hasn’t been made available yet. It was supposed to be available from Amazon.com at the end of January, but it looks like they missed their date.
I suspect that once Amazon.com has captured a good chunk of the market, the labels will migrate their catalogs to iTunes Plus so that both sites can compete with one another on equal ground. In the meantime, they’re playing favorites to escape from the clutches of Apple. One thing that’s interesting to me is that Amazon.com is actually lowering the price of music downloads, I’m not sure where that fits into the labels’ plans.