The US government, more specifically the Library of Congress, today issued a new ruling that finds that jailbreaking phones is not illegal. The ruling also makes legal the installation of third party applications and the unlocking of phones for use on other networks.
It’s not immediately clear how carriers and device manufacturers will be affected. It certainly does not appear to prevent them from locking devices but would prevent them from taking legal action against those who decide to do so.
The ruling also allows applies to video games, movies, and hardware dongles under specific scenarios. For example, a student could break the copy-protection on a DVD to include a small clip in a not-for-profit project.