Online retailer has launched a music-download service, offering a catalogue of 300,000 songs from the five major labels.

BuyMusic founder Scott Blum called Apple CEO Steve Jobs "a visionary", but added: "He's on the wrong platform. If you don't support Windows, you cut off 97 per cent of the market."

Apple will launch a Windows version of its service later this year, with some reports hinting that the service will go live in the autumn, in time for the peak US shopping season.

Blum told USA Today: "The iPod is the best little product I've ever seen, but it's like building the best car in the world that doesn't use the right gas."

The new Windows-friendly service – which benefits from a $40 million wave of publicity and advertising in the US – does not offer consumers the same level of usage rights as Apple's service.

It permits the labels to apply limits, such as limited CD-burning sessions, for some tracks. Music costs about the same as it does from Apple, though at 79¢ some tracks are cheaper. Most of the available catalogue is accessed through a Web site, rather than from within an integrated software solution, as with iTunes. The catalogue can be kept on an external digital-audio player.

Incompatability Because the service utilizes Windows Media Player 9 tracks acquired from BuyMusic will not play on an iPod.

Blum expects to sell millions of tracks through the new service, reflecting Apple's achievement in selling 6.5 million songs in the first 61 days of the iTunes Music Store's existence.

Content is central as the new music services carve out a niche for themselves. Apple, for example, has already begun offering content and information that's unavailable elsewhere.

For example: on July 15 Avril Lavigne made a five-track EP called My World that is available only through the iTunes Music Store, although full-length CD and DVD equivalents will be released in October. Lavigne, currently America's biggest-selling singles artist, instantly became the biggest selling artist on Apple's Store.

This digital release will not be distributed by other digital download services until August 15.

Commenting on, Raymond James and Associates analyst Phil Leigh said: "The service represents the first a la carte digital download service for Windows."

It will not be the last, he affirmed, quoting EMI vice president Ted Cohen, who said: "By the time students are back in their dorms there will be many legitimate choices."

Looking at BuyMusic's $40 million advertising plans, Leigh said: "We believe this campaign will benefit not only but the entire industry by bringing media and consumer attention to the concept of legal downbloads at a reasonable price."

Praising Apple's service as providing the most consumer-friendly service now available, Leigh points out that's prices are in line with those of Apple, which analyst Charles Wolf has described as hitting consumers’ "sweet spot".

Leigh observed: "BuyMusic's pricing is very similar to what was already prevalent in the market, alleviating concerns that it would initiate a pricing war."

Leigh added that an industry conference will take place next week. "We would not be surprised to see additional announcements related to online music there," he said.