Well it was only going to be a matter of time. I've seen a couple of infected Apple mobile devices this year and the point of infection was through browser exploits. I've also had users come in with infected Macbooks because the Apple store advised them to not download AV. Apple have been under constant attack since the primary user of an Apple device changed from a graphic designers/wacky 'alternative' types to your average Windows user.
While Apple continue to put up a fight it will still be a good deal more secure than 99% of Android devices just down to how they are able to push out updates without relying on manufacturers to modify the update for specific devices. It'll be interesting to see how secure the new Android based Blackberry devices are.