Napster is previewing its forthcoming Napster To Go service.

This service leverages new Windows Media 10 technologies to enable Napster subscribers to download music to portable devices, a technology called Janus. Music remains protected, and if a user's subscription ends, the music won't play any more. It's tunes to rent.

The final version of Napster To Go, with enhanced functionality and compatibility with a range of MP3 players, will be available in autumn as part of Napster client 3.0.

Napster CEO Chris Gorog said: "We are putting our stake in the ground as evidence of our commitment to lead and not follow by introducing this highly-anticipated and game-changing capability in preview and look forward to offering music fans the enhanced final version in our updated client this fall."

The capacity to carry subscribed music in this way is only available using a Windows Media Player 10 plug-in, and only currently works with the Samsung Portable Media Center or Creative Zen Portable Media Center.

Napster 3.0, featuring Napster To Go, launches in autumn when more third-party devices are expected to support the technology. Renting, but not owning, music using the service currently costs $14.95, but final prices have not yet been declared.