Looking to overturn a longstanding Library of Congress decision to Fort Knox your gadgets to a specific carrier, the "Unlocking Consumer Choice and Wireless Competition Act" (S.517) just hurdled its second major obstacle on its way to becoming a law. Now, the bill only needs the POTUS' signature and smartphones will be able travel among carriers uninterrupted. This is all pretty much a formality as the president has come out in support of the policy.
So what does all this mean for you? Most phones only work on specific networks. If you want to use your phone on another network, it needs to be unlocked. As it stands now, you need to get your carrier's permission (to do something with a device you already bought). This bill protects customers as well as third-party professionals who provide unlocking services, so you can purchase a smartphone from one carrier and be able to use it on another carrier if needed. So that you own that device you bought, and can do what you want with it. This bill also extends to not only smartphones, but tablets and other carrier-dependent devices.