Verizon's V Cast Music store now provides MP3s — unprotected music files — through a $15 monthly subscription. The service includes downloads to mobile units or PCs.

MediaPost believes the move could improve Verizon's market share in mobile data. And it will certainly broaden the digital music market beyond iTunes.

The $15 subscription gives users unlimited access to songs from the Big Four music labels. Non-subscribers can download tracks for $0.99 apiece. RealNetworks' Rhapsody powers the service.

Verizon follows a number of established brands into the DRM (digital rights management)-free music sector, including Napster and Amazon. The user-friendliness of DRM took a serious blow when Microsoft said it would stop providing license keys to former customers on MSN Music, potentially robbing paying users of the ability to play their tracks after August.

Image credit: pinkbelt.