Meanwhile testers of Apple's iOS5, the upcoming version of its software powering the iPhone and iPad, said the new iTunes Match service announced in June by ex-chief executive Steve Jobs, allows users both to download copies of songs from their collection, or just listen to them without downloading if they wish.

iTunes Match works by first scanning the user's music library that resides on their principal computer. Any songs that already exist in Apple's master library are then immediately available to stream or download to another device such as an iPhone or iPad; songs which Apple does not sell are uploaded and become available later. When Jobs announced the service in June he only mentioned the downloading capability - but Apple may have since signed licences which allow it to add streaming.

"All your music - up to 25,000 songs - will be accessible from your various computers and iOS devices," said Arnold Kim of the MacRumors site. "What wasn't clear before is that music can be either streamed or downloaded. This [streaming option] means your music library won't need to take up valuable space on the device itself, as long as you have some sort of internet connection."