Due to a ruling by the Librarian of Congress, come tomorrow it will be illegal to unlock a new, on-contract iPhone -- or any phone -- in the U.S. If you bought your iPhone before tomorrow, or if you bought a factory unlocked iPhone straight from Apple, or off-contract, full priced iPhone from carriers, or your contract is over, you shouldn't be subject to any restrictions. Doing it on your own via Jailbreak, however, will be strictly verboten, and likely subject to prosecution by law enforcement and the Batman.