start selling non-DRM music files made headlines.
If you'd like a good layman's analysis of the story, check out NPR's story from today's Morning Edition.
How successful will Amazon be in their new undertaking? Hard to predict. The vast majority of legally downloaded music flows through Apple's iTunes Store. They've pioneered the process and have built an attractive web presence that gets the job done pretty easily, even for the non-tech savvy (I'll testify to that after watching my wife happily buy songs for her new iPod last night).
I use Amazon a lot -- it's a convenient way to find books and music online, and they've earned my trust. I imagine I'll give their new music store a chance, but it's a free marketplace -- if it has what I want and it's easy to use, I'll come back. If it doesn't -- well that's the free market.