Apple's hit online music service iTunes has been made available to millions of PC-using fans for the first time.
Apple's iTunes is now available for users of Windows XP and 2000
The software, which offers tracks for 99 cents (60p), was launched for the Windows platform in the US on Thursday.
It had previously only been available to users of Apple Mac computers - who bought 13 million tracks in six months.
iTunes' expansion is part of a plan to corner the growing market for legal online music, and is expected to become available outside the US next year.
It will boast a catalogue of more than 400,000 songs by the end of October.
Despite only being available for the Mac so far, iTunes accounted for 70% of all legal downloads as of last week, Apple chief executive Steve Jobs said.
A string of services are currently competing for business
But Windows-based PCs account for more than 90% of home computers, while Macs have a 5% share.
Jobs also set the target of selling 100 million songs by the service's first anniversary at the end of April 2004.
"We think taking it to Windows is going to be huge," he said.
"The iTunes Music Store has revolutionised the way people
legally buy music online, and now it's available to tens of millions more music lovers with iTunes for Windows.
"While our competitors haven't even come close to matching our first generation, we're already releasing the second generation of the iTunes Music Store for Mac and Windows."
The new service is available to users with Windows XP and 2000 operating systems.
Bono said Jobs was "the Dalai Lama of integration"
At its launch on Thursday, Jobs spoke to the Rolling Stones' Mick Jagger, hip-hop star Dr Dre and U2 frontman Bono via video link.
"It's like the Pope of software meeting up with the Dalai
Lama of integration," Bono said, referring to the meeting of Microsoft and Apple.
Jobs also announced a deal with Pepsi to promote iTunes.
Internet and music companies are battling to win over fans to new legal download services and away from other hugely popular but unauthorised sites.
Napster is to be relaunched as a legitimate paid-for service at the end of October, four years after it burst onto the scene as a free, unsanctioned site.
And other websites like MusicMatch, BuyMusic and MusicNow have also launched pay services, with more on the way.
Josh Bernoff, analyst with Forrester Research, said: "There's going to be a lot of jockeying for position in the
next 12 months.
"But I think iTunes is a real winner because it has the portable player, the jukebox and the store all together."