Can an iPad, iPod or iphone get a virus?

And great news for antivirus companies even if there are none in the wild.

In other words, those that worry can't enjoy the sunny day at the beach.
Bob

In theory they can only run code that Apple authorizes, so in general, no they can't because Apple would never authorize a virus.

However, there are always bugs in software including the iPhone's iOS and in the past it has been possible for hacker to create very special web-sites and even SMS messages that exploit these bugs and get around the access controls and allow the hacker to run any code including viruses. However, these holes are normally plugged quickly after being found.

Some people disable these controls deliberately by "jail-breaking" their phone. These phone's are much more vulnerable to viruses, and simple viruses that attack jail-broken phones have been seen in the wild, but this isn't something for normal users to worry about.

So in general, it is unlikely at this time, and although this kind of protection is probably at least as good as a virus scanner - if not better - there is always a chance of a big hole being found in iOS and somebody exploiting it.