If you thought that your computer was the only battleground for combating malware (viruses, worms, and the like), think again. If you have a mobile phone that has bluetooth technology, you might be prey to malware as well!
I often keep my mobile phone's bluetooth turned on for transferring photos from my phone to my computer. Today, while I was in town, I noticed that an unknown phone was trying to connect with mine through bluetooth by sending me files of type .sis with names such as irsli3wp2js.sis. Luckily, I knew not to open the files. Once you click on the file and allow it to be installed, such viruses can infect your phone and then start looking for new devices in the vicinity to infect.
A host of worms and trojans are out there that infect mobile phones and also transfer themselves through the bluetooth connection. You can read more about mobile viruses on Wikipedia.
How to protect yourself? To avoid the malware that uses bluetooth technology, you can turn off your bluetooth when it is not in use or set your phone to "hidden" or "undiscoverable" while you're not using it. When mobile phones are used for carrying out sensitive actions such as financial transactions, then it is clearly worthwhile investing in security measures such as mobile phone security software.