Amazon.com is planning to launch a music download store in May, according to Billboard. The article implies that Amazon wants its store to sell unprotected MP3 files that don't come with the digital rights rules that accompany songs sold by other stores.

Amazon had planned to launch a digital music subscription service and its own handheld player, according to the article, but dropped those plans last year.

The trend is clearly moving away from digital rights restrictions on songs. EMI Group said earlier this month it would begin selling songs on Apple's iTunes store that were free of restrictions. But they'll cost $1.29 compared with iTunes' normal 99-cent fee.