Apple is hinting at a major revamp of its iPod music player range next week, after sending out invitations to an event in San Francisco on 7 September.

"One thousand songs in your pocket changed everything. Here we go again," the invitation stated.

The comment refers to the original launch of the iPod four years ago, which was one of the first hard disk-based digital music players at the time. Competing products used more expensive flash memory.

While the move resulted in mixed reactions, Apple has since conquered the market for digital media players.

Next week's event could see the launch of a video iPod, rumours of which have been circulating for some time. 

Apple is said to have been talking to record companies about licensing music video downloads, and the company earlier this year equipped its iPod players with a colour screen.

An upgraded version of the flash memory-based iPod Shuffle could be another option. According to analyst firm iSuppli, Apple has recently signed a contract with Samsung Electronics to guarantee a steady flow of memory chips for the music player.

A third option would be the launch of the Motorola iPod mobile phone. The model's introduction has missed several deadlines and has been development for a long time. But things appear to be progressing after the handset received approval from the Federal Communications Commission.

The current version 4.9 of the iTunes media player also offers some support for mobile phones.

Industry insiders, however, maintain that operators are refusing to support the phone because it would force them to loosen control over the lucrative ring-tone business.

They also seek guarantees that the devices are synchronised over a cellular data connection rather than through a wire, ensuring them additional customers for data plans.

To circumvent the operators Apple could decide to set up a mobile virtual network operator where the company launches a new mobile brand and leases network capacity from an operator that owns a network.

Virgin Mobile already operates such a network in the UK and US, as does Disney in the US.