Mobile gadgets, such as smart phones and personal digital assistants (PDAs), are vulnerable to viruses written for them, but the threat is still relatively small. No mobile gadget virus has run rampant through the world's pockets in any notable wayyet.
The current crop of viruses attack Nokia's Series 60 smartphones that run the Symbian operating system, which is the world's most dominant mobile operating system. However, it is installed on only 2%3% of mobile phones worldwide.
One virus, called Cabir, jumps between devices using Bluetooth, a short range wireless technology designed for gadget-to-gadget data transfer. The virus Commwarrior uses multimedia messaging service (MMS) to transfer the virus. Normally MMS is used to send pictures and audio between phones. And the Skulls virus spreads into a Symbian smartphone inside another program.
The upshot is that you really have to work hard to infect your gadgets with a virus. That might change as gadgets evolve and get more powerful, like computers, but for the time being your devices are mostly safe from viruses.