Microsoft said Monday that phone maker Nokia has joined its PlayReady digital rights management program for mobile devices. Nokia will use PlayReady DRM technology in its S60 and Series 40 mobile devices.

Microsoft bills PlayReady as "content access technology" that mobile operators can use to ensure that music, videos, and other content available on their networks has appropriate copyright authorizations and broad device compatibility. It's an extension of the company's PlaysForSure DRM program for digital music players.

Microsoft's contention is that broad industry acceptance of such programs will make it easier for end users of digital devices to download, play, and share content without having to worry about device support or copyright violations.

Microsoft introduced PlayReady in February. At the time, the company said mobile operators O2, Verizon Wireless, AT&T, and others had expressed interest in the technology. Nokia is the first mobile vendor to publicly announce its intention to use PlayReady.

Mobile devices equipped with PlayReady will be able to play DRM-protected content stored in a number of formats, including Windows Media Audio, AAC/AAC+/HE-AAC, Windows Media Video, and H.264.

If mobile operators are slow to embrace PlayReady, it may be in part due to Microsoft's spotty record when it comes to following through on such programs.

The company introduced PlaysForSure for MP3 players in 2004. The idea was to create a digital music ecosystem that included mobile device makers, online music stores, and the recording industry. Microsoft, however, surprised the industry in 2006 when it launched the Zune music player without PlaysForSure compatibility.

Instead, Microsoft tied Zune to its own Zune Marketplace online store in an effort to step up one-to-one competition with Apple's iTunes program.

Microsoft has said it continues to back the PlaysForSure program.