I am sorry, thewitt, but that statement is only half right. ALL iPads are subject to viruses.
See the link that Drag Bunt posted above (#5). Apparently, iPads are vulnerable to PDF exploits (through Safari or even iBooks). And, that’s just one little thing – I’m sure there are more.
The jailbreak the c0mex developed (and released in July 2011) was based on a PDF exploit. A PDF exploit that Apple either did not know about or did nothing about. So, thousands of iPad users were able to easily jailbreak their iPads using this exploit. It's still available today.
The most interesting aspect of this is that c0mex also developed a patch for this exploit. So, if you wished, once you jailbroke your iPad, you could install the patch and thus protect your iPad from that very same exploit. So, jailbroken iPads, for a time, were less vulnerable than stock.
As we know, Apple did come out with an update to also fix this patch (iOS version 4.3.4). But, it was after the fact of the exploit's existence was known, publicized and used. And, as far as we know, there could be more…
The point is, all iPads are vulnerable. However, while jailbroke iPads do have more “freedom,” they still share Apple’s basic premise of “sandboxing,” where Apple deliberately took the decision to isolate ('sandbox') apps to prevent a virus from infecting another app or the iPad. This isolation means an iPad is immune from computer viruses because one piece of malevolent code simply cannot affect another legimate piece of code. Yeah, some stuff can (could?) get messed up within an app - but it won't spread.
So, for now, we all are pretty safe … but, we can never let our guard down or make assumptions. Someone, somewhere, wants to cause havoc to our iPads (and thus Apple). They may get lucky someday and all we can be is viligent.
And yes, Apple is going to help us in this ... but stuff will still sneak through. It really is a matter of time, IMNSHO. No computer is safe - you can only practice safe use.
Marilyn