The songs from the Rolling Stones, Coldplay and Maroon 5, among others, will play on most portable media devices, including Apple Inc.'s iPod.

Although many independent music labels have for years sold their tunes without copy restrictions, major recording companies have insisted on digital-rights management, or DRM, technology in hopes of curbing online piracy.

DRM has been the source of consumer frustration. Copy-protected songs sold through iTunes, for instance, generally won't play on devices other than the iPod, and iPods can't play DRM-enabled songs bought at rival music stores.

Britain's EMI Group PLC earlier this year became the first of the major labels to embrace DRM-free tunes, letting Apple sell DRM-free versions of songs with higher audio quality for $1.29 per track.

Earlier this month, Vivendi SA's Universal Music Group — the world's largest recording company — made a portion of its catalog available online in the DRM-free MP3 format. Its test, which runs through Jan. 31, excluded iTunes.

Other outlets are also selling DRM-free music, including Amazon.com Inc., Best Buy Co. and RealNetworks Inc.'s Rhapsody. The format is also sold through gBox Inc., which gets referrals from Google searches for Universal's music.