Company's shares jumped 11 percent on news.

Napster is offering free music again, but this time it’s legal.

Napster, Inc. re-launched its Web site today (May 1), allowing users to search and listen to any song in its 2 million-track library free for up to five plays. The service does not require users to download any software, only register with a valid e-mail address.

The new service relies on advertising to compensate record labels and artists, who will share in the ad revenue the site generates. The company is selling banner ads on the site, as well as including premium audio and video ads in the music player.

Once a song has been streamed five times, listeners are offered the chance to either buy the track for 99 cents, or subscribe to one of the company’s monthly usage plans.

The service also provides links that users can embed into e-mail, instant messages, blogs or Web sites to let others stream songs free as well. Finally, the company added a public music archive called the “Narchive”—a site where users can upload personal stories, photos and other data to what amounts to a community blog of sorts. is available on all operating systems and Web browsers in the U.S only, but the company says it has plans to extend the service overseas in the near future.