MTV, the US cable television music channel owned by Viacom, will launch a digital music download service tomorrow designed to compete with Apple Computer's highly popular iTunes service.

The service, called Urge, will use Microsoft's latest Media Player technology. It is a serious challenge to Apple's dominance of the legal digital music download market.

Steve Jobs, the chief executive of Apple has been the driving forced behind the company's iPod music player and accompanying website iTunes.

Microsoft and MTV executives said the service would target the growing market of people without iPods.

Other rival music download services have had limited success, but none has had the marketing muscle of MTV or been as tightly integrated with Microsoft's technology - the latest version of Windows Media Player software will launch with Urge this week.

Users will be able to download individual music tracks for 99 cents each - the same price as iTunes - or sign up for an unlimited subscription service for $9.95 a month or $14.95 if subscribers want to load the music on to a portable player.

Urge will have more than two million music tracks from 110,000 artists, 500 playlists, 130 streaming radio stations and more than 20 blogs written by music experts.

Van Toffler, president of MTV Networks, said the company had been working on the new service with Microsoft for months and noted that digital downloads still represented a small fraction of overall music sales. "Only 5 per cent of music is sold digitally," said Mr Toffler.

"We are just getting going. We will concentrate on people who don't have iPods."