Napster LLC (formerly Roxio Inc.) is an online music provider offering a variety of purchase and subscription models. The company's name and logo are derived from the infamously free Napster peer-to-peer file trading service, which was shut down after a series of legal actions taken by the RIAA. The brand name was later purchased by Roxio, to capitalize on the notoriety and popularity of the former service.
Currently Napster is a well-known music subscription service which delivers music files in WMA format (Windows Media Audio).
TuneRaft can convert Napster files to mp3 and other unprotected formats if you have valid licenses for playback of those files on your PC.