If you own an iPhone and you're sick of AT&T's horrible plans and even worse service, and you live in the United States, there's some good news for you. The Library of Congress' Copyright Office has ruled that is not illegal to jailbreak your iPhone to bypass its security for use on other cellphone service providers. Not only is this not illegal, but it does not void the warranty of the phone. This also will allow you to install and run applications not officially supported by Apple.
This flies in the face of Apple's original claim that people who buy an iPhone are just licensing the right to use that property and were not owners of that technology. As such, the modification or destruction of said property would render the customer in legal trouble. Many Apple users, not just for the iPhone, were disgusted by this new policy. And, honestly, if you're paying more than double the money for a piece of technology just because it has the Apple logo on it, you should be angry. The Copyright Office went on to say that any OS on any smart phone with independently developed applications falls under fair use, so Apple didn't have a case. It's a concept that is foreign to Apple.
So those of you out there who love the iPhone and have been waiting for the chance to switch to another service, here's it is. Apple can no longer force its customers to use AT&T.
Source:
http://www.computerweekly.com/Articles/2010/07/27/242100/iphone-jailbreaking-not-illegal-says-us-government.htm