Sony BMG Music Entertainment is joining Amazon's MP3 party, and will allow its music to be sold via the unprotected format on the digital download store. The move comes on the heels of Sony BMG's announcement that it will sell album specific digital download gift cards that will be redeemed in the MP3 format.

While the latter announcement was limited in scope to 37 albums, the Amazon agreement represents a broad acceptance of the MP3 format by Sony BMG, which up until now, had been the major deemed the most resistant to abandon the concept of music protected by digital rights management software.

"We are excited to be working with Amazon as they continue to build new markets for digital music," said Sony BMG Music Entertainment global digital business & U.S. sales president Thomas Hesse, in a statement. "We are constantly exploring new ways of making our music available to consumers in the physical space, over the internet and through mobile phones, and this initiative is the newest element of our ongoing campaign to bring our music to fans wherever they happen to be."

An exact date has yet to be set for when Sony BMG's music will be available at Amazon; the press release simply says later this month. But that will be in time for the giant Pepsi/Amazon download and other merchandise give away promotion that will be launched in early February. Sources say Sony BMG will be one of the three majors participating in that promotion.