The long-discussed phone virus threat is apparently already calling. The good news is that the virus is relatively harmless and not terribly efficient. The bad news is that, like computer-virus creators, the writers of mobile-phone viruses will likely only get better.

F-Secure Corp., a Norwegian security firm, is now analyzing a new mobile-phone virus that appears to replicate itself via multimedia messaging. According to F-Secure, the virus appears to be Russian in origin because some code in the virus translates from Russian to "No to braindeads." Oh, those Russians. What a laugh riot.

The virus has been dubbed CommWarrior and runs on the Symbian Series 60 smart phone OS, so it will affect a range of handsets, including Nokia Corp. phones. Previous mobile viruses, such as Cabir, used Bluetooth to replicate themselves, which limited their effect. CommWarrior, however, attempts to spread over both MMS (Multimedia Messaging Service) and Bluetooth. MMS is a mobile technology used to send text messages that can also include images, audio, and video. It"s built into devices from Motorola Inc. and others, as well as into the Nokia phones.

Why should we care about mobile-phone viruses? Well, imagine a virus that gets in your phone, begins dialing 1-900 phone numbers, and downloads data that gets added to your phone bill or your company"s phone bill.

Thankfully that hasn"t happened yet, and it"s hard to tell when it might come about. For one thing, although CommWarrior targets a fairly large installed base of phones, there are plenty of other phone-operating systems out there. Targeting each one of them would task even the most energetic of virus writers.

So maybe one simple way to avoid the latest phone viruses is to make sure you or your company purchases phones with different operating systems. Most of the operating systems will communicate with each other, after all, so why worry about maintaining a standard phone platform? Then again, consider reality: Like many families, my family uses the same phones and mobile plan so we can talk to each other for free. If my nephew"s phone gets infected, mine will likely meet the same fate.

If you"re worried about the current threat, here"s some familiar advice: Don"t install unknown applications arriving in MMS messages, and keep Bluetooth in undiscoverable mode. If that sounds similar to the advice given when viruses began spreading via e-mail -- "don"t open e-mail from unknown parties" -- it shouldn"t be a surprise. Common sense may be the best advice of all.