Lauren Berkowitz, a senior vice president at EMI announced this week that "the initial results of DRM-free music are good".

Since the DRM-free tracks from EMI went on sales on iTunes Plus last month they have generally outsold the normal versions of the same music.

EMI confirmed that sales of Pink Floyd's "Dark Side of the Moon" were up 350 percent in the week after iTunes Plus launched.

DRM-free tracks cost more than the same copy-protected songs (20p extra per tune) so take-up of the new format was not certain, but it seems that consumers are happy to pay more.

The DRM-free songs on iTunes Plus are also offered in a higher quality - 256kbps AAC encoding - it's unclear at this early stage if consumers are being attracted by the new freedoms DRM-free tunes offer, the improved quality, or a combination of the two.

EMI are hoping that this success will continue, rather than be an initial upward blip after a highly publicised launch.

This success will be very positive for American Amazon, who have announced plans to launch their own DRM-free download site later this year and hopefully might persuade other large record companies to free up their music too.