Not even the iPhone is safe from would-be hackers, despite Apple's best attempt to keep the device locked down and secure. A "virus" of sorts was recently released, posing as an update for the iPhone, that was actually created to create a bit of malice. This time around, the trojan appears to be without any real harm intended - it doesn't cripple or otherwise render the device unusable, but can disable some other utilities such as OpenSSH. Overall, it was probably meant as a proof of concept..
While sites hosting the package have been identified and removed, it still brings to light the fact that the iPhone is still a mini computer and is still vulnerable to attack. This one may have been fairly benign, but future attacks might not be. It may give some credence to Apple claiming they need a walled garden, but obvious with such a fancy phone people will want to toy around with it - they'll just have to be cautious about what software they trust to put on it. There is no comment from Apple on the trojan as of yet.