Opening for business on Wednesday, music fans will be able to choose from 300,000 tracks available on .
The site will also encourage people to sign Oxfam's global petition, called the Big Noise, and the charity is calling on governments to introduce fair trade initaitves through its Make Trade Fair campaign, which has already been endorsed by 5m people, including the Dalai Lama and Coldplay frontman Chris Martin.
Martin said: "Paying to download from BigNoiseMusic.com seems like a good idea when you know your money is going to help some of the world's poorest people."
For every pound spent on the service, 10p will go directly to Oxfam, with songs available from as little as 75p each.
The technology behind Big Noise Music is being provided by OD2, which also backs the download services for HMV, Coca-Cola and MSN. The Big Noise Music site was designed by digital creative agency Poke.
Napster announced last week that it was launching its UK legal download service. Other recent entrants to the market include Sony and HMV, with MTV rumoured to also be considering a service.
Oxfam has been expanding its lately and now offers a secondhand book search and breaking news service.
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