Millions of iPod owners may be surprised to learn they're suing Apple, industry analysts said.

A lawsuit against Apple by RealNetworks, which developed the Real Player app and the Harmony music service, has been given class-action status U.S. District Court for the Northern District of California, Mashable reported Thursday.

Consumers who purchased iPod devices between Sept. 12, 2006, and March 31, 2009, may soon be getting an e-mail from RealNetworks, Mashable said.

RealNetworks' Harmony, created in 2004, was a digital rights management translation service that allowed users to play songs downloaded from the RealPlayer music store on iPods.

However, Apple issued an iPod firmware update not long after the announcement of Harmony that blocked it and other music services from uploading songs to the iPod.

The lawsuit accuses Apple of unfairly blocking competition.

"The lawsuit claims that Apple violated federal and state laws by issuing software updates in 2006 for its iPod that prevented iPods from playing songs not purchases on iTunes. The lawsuit claims that the software updates caused iPod prices to be higher than they otherwise would have been," Web site ipodlawsuit.com said.

Owners of first- through fourth-generation Nanos, second- and third-generation Touches, first- through third-generation Shuffles, a fifth-generation classic iPod or the special edition U2 iPod are automatically included in the lawsuit, Mashable reported.