Apple has launched iTunes Plus, featuring DRM-free music tracks featuring high-quality 256kbps AAC encoding for what it call "audio quality virtually indistinguishable from the original recordings". Each DRM-free song costs 99p.

Digital rights management (DRM) refers to technologies used by publishers or copyright owners to control access to or usage of digital data or hardware, and to restrictions associated with a specific instance of a digital work or device.

With the release of iTunes Plus, customers can now download tracks from EMI artists without limitations on the type of music player or number of computers that purchased songs can be played on. iTunes is also offering customers a simple, one-click option to easily upgrade their library of previously purchased EMI content to the iTunes Plus versions.

iTunes Plus is launching with EMI’s digital catalogue of outstanding recordings, including singles and albums from Coldplay, The Rolling Stones, Norah Jones, Frank Sinatra, Joss Stone, Pink Floyd, John Coltrane and a stack of Paul McCartney albums.

The company released an update to iTunes (version 7.2) last night, introducing support for new DRM-free music sales, a move first promised by Apple CEO Steve Jobs and EMI CEO Eric Nicoli in April.

"With iTunes 7.2, preview and purchase iTunes Plus music - new higher-quality, DRM-free music downloads from participating music labels," Apple urges in notes accompanying the software.