Sales of Apple's iPod MP3 player may be boosted by news that sales of digital-music devices will double in the US.

A study, conducted by Harris Interactive, surveyed almost 2,000 people aged 15 to 35. More than 50 per cent said they'd buy a digital device in the next year.

At the moment, 21 per cent own at least one portable audio-digital product.

The survey also evaluated the use of Internet portable-audio devices, including MiniDisc players, MP3 players, CD-R/RW players, Memory Stick, Walkman recorders and other flash-media players, to transfer and listen to digital music.

Robert Ashcroft, senior vice president of Sony Electronics' Personal and Mobile Products Division, said: "The study shows us that consumers want to enjoy customized music mixes anytime, anywhere.

"Music lovers have figured out how to download digital music and customize their collections on the PC. Now they are looking to transfer those collections to a portable device."