MacRumors reports that jailbreaking the iPhone is now officially allowed in the US

While it is not uncommon for users to jailbreak their devices, the practice is officially unsanctioned by Apple. The company maintains a support document outlining some of the issues users of jailbroken iOS devices may experience while also disclosing that Apple reserves the right to deny service for any such device due to the "unauthorized modification" being a violation of the license agreement. Under the new federal policies, it would appear that Apple is no longer permitted to deny service for such reasons under the Digital Millennium Copyright Act, although the company could likely still argue that the device's Terms of Use allow it to deny service.

  U.S. Government to Explicitly Allow iPhone Jailbreaking