Willco said:
How does a virus infect mobile phones? Text messages?
Turn off bluetooth and don't download bootleg content and you're generally safe. Same rules apply as using PCs, though much of this has to do with Nokia's own incompetence.
A big problem with dealing with this situation on phones is that phones have no inherent mechanism to receive automatic firmware updates. This is a problem at the core of cellphones. Put 30 of the same model of phone in a room and they probably all have a different firmware/OS level release. As such when people like Nokia say they have fixed the problem, what they really mean is that they have fixed it in any future phone that they put out and everyone else is screwed.
This is more a wakeup call that phone manufacturers and carriers are totally irresponsible bordering on criminally neglegent when it comes to actually protecting these devices and that has more to do with their genuine business interests than technical limitations. Of all the carriers everywhere, only Sprint has any tangible plans to build an upgrade service for phones.