Flying Officer Kite,
Certainly, it would appear that hackers have managed to unlock the new iPhone 2.0 software, meaning that the iPhone could be run on any network. However, you have to deliberately run software in order to re-flash the iPhone to make it work. This is different from being able to do damage to a desktop via the iPhone in terms of viruses and dangerous code. Like fleebag, I've not seen anything along these lines.
What sort of problems are you having with downloading?
AppleMacster