On Friday President Obama signed into a law a bill allowing mobile devices to be legally unlocked, so that consumers can switch between carriers. The legislation was kicked off by a successful petition on Whitehouse.gov after the Librarian of Congress decided that cell phones no longer needed an exemption from the Digital Millennium Copyright Act's anti-hacking provision. The legislation (PDF) passed both houses of Congress and is now law. Unfortunately, the new bill doesn't guarantee permanent legality. It simply reinstates the exemption, and leaves the DMCA alone. For the next year, cell phone unlocking will certainly be legal, but after that, the Librarian of Congress once again has the ability to void the exemption once every three years.