The agreement with the UK's Association of Independent Music and its European counterpart covers music from artists such as Moby, Underworld, Tom Jones, Ash, Moloko and Stereophonics.
The agreement boosts Napster's plans to launch a legitimate, subscription-based song-swapping service later this summer, where music from the independent labels will be available alongside music from record industry majors BMG, EMI and AOL Time Warner.
Napster is working towards this model after a US court slapped an injunction on the company preventing it from allowing users to swap copyrighted music files.
Yesterday, a court of appeals refused the company's request for a hearing to overturn the injunction. Unless Napster makes another appeal to the Supreme Court, a full-blown trial could lead to Napster paying millions of dollars in damages to record companies.
Napster believes that its subscription service will be ready by then, and it is confident that the service will allay the concerns of the recording industry.