By Jim Reed
Newsbeat technology reporter
The latest albums from Leona Lewis and Mark Ronson are available
One of the world's biggest record labels has made its complete back catalogue of songs available free over the internet for the first time.
Sony BMG, which is the home to artists like Britney Spears and Michael Jackson, has signed a deal with the music website We7.
Users can listen to 250,000 songs for free but have to wait for a 10-second advert between each track.
The site includes albums from the likes of Leona Lewis and Mark Ronson.
The complete back catalogues of artists like Michael Jackson and Elvis Presley are also available.
The boss of We7, Steve Purdham, told Newsbeat: "You can pay for a track with money, but most people don't like to do it these days. So the deal we are giving is free music in return for some of your time."
We7 builds a profile of each individual user. So a 20-year-old from Scotland and a 35-year old from Cornwall will both hear a different, targeted commercial even if they are listening to the same song.
The free tracks are only available directly through the We7 website itself. Users still have to pay to download a track to a computer or a digital music player.
Steve Purdham said: "Apple's iTunes changed the landscape in terms of delivering digital music. But consumers have proven that, for every one track you buy, there are 99 tracks that no one pays for.
"So, in the new economy, it's about giving consumers the choice."
For years, the music industry has tried to clamp down on people who share copyrighted songs over the internet.
But research shows that more than four million people in the UK still use peer-to-peer services like Bittorrent that let you swap tracks.
The average iPod contains £750 worth of music, half of which has been copied from unpaid sources.
Ninety-five per cent of all 18-24 year olds regularly copy music from their friends, according to British Music Rights, which speaks for musicians and composers.
Some music companies, like Sony, have been experimenting with different ways of selling music in an effort to cut the amount of piracy online.
An average iPod contains £750 of music - half from unpaid sources
A large number of new music services are expected to start operating before the end of the year.
The mobile phone company Nokia is planning to launch its Come With Music service in the autumn.
The deal will allow you to download an unlimited number of tracks to a new Nokia phone and a computer over a 12-month subscription period.
When the subscription runs out, the user can still access any track in their music library.
Both Sony and another major label, Universal Music, have already signed up and Nokia is confident of getting the other two big music companies, Warner Music and EMI, to agree before it goes live.
The social networking website MySpace is also expected to launch its full music service before the end of the year.
Users will pay to download tracks from the site to their home computer.
But it is also thought a large number of songs will be available free of charge if you agree to listen to a short commercial first.