Eminem's record company has filled a lawsuit in Detroit, seeking to stop the illegal use of the rapper's songs.

Michigan-based Eight Mile Style and Martin Affiliated filed a suit in U.S. District Court in Detroit on Tuesday, against five big mobile companies, who are currently using Eminem's songs as ringtones, selling them over the Internet.

"This is a big business. We're talking hundreds of thousands of dollars a year," said Howard Hertz, a Bloomfield Hills-based lawyer for the companies and for Eminem.

The firm also plans to sue karaoke companies that sell Eminem songs without getting the proper licenses.

"We're going to be going after any ring tones or karaoke companies who use his songs without getting the proper licenses," Hertz said.

Jupiter Research said in a March report that ring tone revenue is growing nationally, having more than doubled, to $217 million in 2004, and will reach $724 million in 2009.

Cellus USA, FanMobile, Nextones.com, MyPhoneFiles and MatrixM LLC are the companies that were named in the lawsuit.