A group of virus writers developed the worm and sent it to anti-virus firms.

When the virus strikes it makes the mobile phone display the word "Caribe". It spreads using a phone's ability to send wireless Bluetooth signals.

As the virus, called Cabir, was developed by experts it is harmless. But some say it proves that mobile are also at risk from virus writers.

No mobile phone infections have been reported so far, but anti-virus firms can't agree if this means we'll see loads of phone viruses in the future.

Threat to phones

Some experts think people should take the threat seriously, and we need to protect mobile phones with special anti-virus programes like we do with computers.