Every time a new device comes to market people go to work looking for ways to hack into the device to modify either its hardware, software, or both. iPhone is no different, and people are having success.
So far people have found several ways to activate a new iPhone without first signing up for an account with AT&T - the telecommunications company with an exclusive deal to provider cellular service to iPhone users.
Activating the phone without cellular service lets people use the phone as a Wifi network device and an iTunes player. Other people are looking for a way to get their hands on the iPhone firmware, and unscramble it. At that point modification can begin, and entire new dimension of security vulnerability can take place.
If you're interested in some of these trends, head over to the So Sue Me blog, and read the comments.