Originally Posted by goaliemn

If anything, Apple may be able to say you violated the license agreement on the phone/device which may have something about modifying the OS on the device.

As others have pointed out, Apple may try to say its a violation of the DMCA since the copy protection on the device was broken, so it could be interesting. If I had an iphone, I wouldn't go near an apple store with it, unless it was back in its non jailbroken state. Its not worth having someone get too upset.