Microsoft has unveiled its own version of Apple's iTunes service to try and make their way into the digital music business. MSN music offers downloads for 99 cents per song and $9.99 for a full album.

MSN music will try to compete with iTunes by offering songs by artists that have never been available on legal music download stores before, such as AC/DC and Metallica.

Microsoft's entry into the online music business sets up a dilemma for many consumers. Microsoft says about 70 portable music players are compatible with the music format used by its online store. But the most popular music player, Apple's iPod, can't play Microsoft's tunes. And Microsoft-compatible players can't handle songs from Apple's iTunes store. So anyone who wants some AC/DC songs on their iPod is out of luck.

RealNetworks has a music store that is compatible with both Windows based and iPod music players. However, Apple has threatened to sue Real and says that future models will not be compatible.

MSN Music store is only available on computers running the Windows 98, 2000, or XP operating systems. A Microsoft spokeswoman said that support for Apple or other computers might be added later if enough consumers requested it.

MSN Music offers some features that iTunes does not have. If a user can't find an album on the service, he is given a link to Amazon.com, where he can order a copy of the CD. Subscribers to Microsoft's MSN online service can also pay extra for an Internet streaming music service that offers a variety of music styles, such as rock or jazz. This service has been linked to the MSN Music store, so that a listener who hears something he likes can instantly purchase a copy.

It is unlikely that Microsoft will profit from this service, but it may lessen Apple's control of the digital music industry.