Originally Posted by Hypnodisc:
“This is bang on! The same way Mac computers can't really get viruses because of the operating system security, iPhones and iPads are immune too (or rather, it would be extremely tricky to write some sort of bug).”
It's not at all the same way.
The simplest thing is that iPhones and iPod touches can't run unsigned software.
All software on a regular iPhone must be approved by Apple and obtained through the App Store.
With a normal computer operating system like Mac OS X, Windows or Linux it is up to the user to decide what software can run. If the user allows a virus to run then it can do what it likes to their computer, that would simply not be possible with iOS.
Other mobile operating systems (like webOS, Android, Symbian and Windows Mobile) have similar approaches to iOS, restricting what software can be run.
The same security restrictions apply to devices like Games Consoles and Set Top Boxes, which are simply not allowed to run any unauthorised software (like a virus).