If you're using a S60 phone from Nokia, watch out. Kaspersky Labs has just discovered the first trojan, Troja-SMS.Symb.OS.Viver, that will affect the S60 OS. If you mistakenly download this from the internet and install this on your phone—which is easy to do, since it's mislabeled and disguised as a useful photo editor or video codec pack—the virus will start sending out SMS messages like nobody's business.
Why should you care? Because these SMSes are sent to premium ringtone downloads and other services, which will cost you between $1 and $10 per message. Ouch.
If you really want to keep your phone safe from Trojans, check out the video above from our time at CES.