Despite Apple CEO Steve Jobs' insistence that it's just about the music, the iPod, and othe digital-music devices, will incorporate PDA functions as hard drives become smaller and cheaper, according to an industry guru.

Analyst Jakob Nielsen told The Financial Times: "As the pods go up in gigabytes, it's inevitable that they will become general purpose storage devices. Add a colour screen and they become photo viewers.

"PDA-type features are a convenient adjunct to these devices and that convergence is inevitable: All a PDA needs to become a music player is a higher quality chip and a headset plug.

"Usability will be enhanced in contrast to other devices which become clumsy by combining two incompatible features. Soon there will be no distinction between the two categories, other than brand names and which features are emphasised in advertising."