The songs will not have DRM (Digital Rights Management) technology, which puts restrictions on how music can be transferred between devices and PCs, and will be compatible with Apple's iPod line.
Music will come from most of the major record labels, which have increasingly moved to offer tracks without DRM in order to boost the attractiveness of buying music online.
Rhapsody, which is owned by RealNetworks, will match Apple's pricing: US$.99 per song, or $9.99 per album.
Rhapsody one-upped Apple by letting users listen to an entire song before buying. Apple only lets users sample a 30-second clip. Rhapsody lets users preview 25 entire songs per month, or an unlimited number for registered members.
Rhapsody will continue running a music subscription service that is incompatible with iPods. Users pay a monthly fee, starting at $12.99, for access to a large catalog of songs, which can be transferred to a portable device but are rigged with Windows Media DRM to disappear if the subscription lapses.