Nokia is looking into it, but hasn't confirmed it yet. If it does prove true, it will probably require an update to the affected phones, since the lockup apparently lasts until you cut power to the phone (read: remove the battery and put it back on).
The article ponders whether the exploit might lead to viruses. I'm somewhat skeptical of this; while sending a code to lock up the phone may be possible, that's completely different from sending a code that sends a code to every number in the phone's directory, for example. Besides, the fact that the message locks up the phone sort of kills any chance of replication. :-)
Still, if the issue is in fact real, it highlights the ease with which a wireless device can be affected by someone with malicious intent. I'm sure situations like this are only going to become more prevalent as the predicted merger of cellphones and PDA's begins to occur.