Early adopters are an impatient lot, especially Apple boys and girls. With Macworldlooming Tuesday (a 3G/GPS iPhone? I will so be in line to get one if or when it comes out) and with reportsof impatient iPhoners being hit with a Trojan masked as "leaked" 1.1.3 firmware, you can see that the line between enthusiasm and caution can be thrown to the wind.
While there don't seem to be any lasting or major effects from 1.1.3 Trojan, it made me wonder, when the iPhone is finally opened up for "legit" third-party developer applications, how common hacks like this will be in the future and how many more people will be affected by them. The 1.1.3 Trojan involved tinkering and hacking, so average Johnny Appleseeds like me, weren't hit. But, I'm sure future Trojans will be more malicious and more insidious, just like PC-based viruses. So, whereas viruses were uncommon in the Mac world (or so I'm told), I would predict this to change.
After asking how current iPhones were affected when an official firmware update hadn't even been released, and after many confused IMs later with my iPhone guru friend Patrick, I was exposed to the nuts and bolts of hacking your iPhone. Apparently, the "shift" key and a disc image becomes important during a sync in iTunes that allows you to install neat things like Labryrinth(the rolling ball game over a pegged-hole game board that takes advantage of the iPhone's accelerometer--so cool) and other applications.
From all that, I gathered that you had to take affirmative steps involving disc images, jailbreaks, and other incantations to have gotten the 1.1.3 Trojan. In other words, it took time and more know-how than I'm willing to devote to get this first round of evil-doing code. But, as the iPhone platform is opened up (next month) and as Apple cedes control over iPhone applications, and as average users like me start to take advantage of them in greater and greater numbers, I do worry about the hassle a future Trojan/virus/worm would cause. Just take a look at the "Free Public Wi-Fi" phenomenon (no, it's not really free, it's more like an innocuous social disease that is really widespread), and just imagine the possibilities if it weren't as benign.