I have had an iPhone since the 3GS was released and I currently have an iPhone 4S. I’ve also had two iPads and will likely purchase the new one when it is released. One thing I have always done to my devices was to “jailbreak” them, a term used to describe unlocking the capabilities of their devices.
Many people jailbreak their devices to be able to install applications that Apple will not let into the App Store. I’ve never liked some of the system sounds that Apple has set up; I have been able to change some of them by jailbreaking and then tweaking the settings. (e.g. Now my unlock sound doesn’t sound like a click, but the Star Trek communicator sound—much cooler.)
Up until 2010 many phone manufacturers declared that jailbreaking their device was illegal and would void any warranty on the phone. On some older iPhones, jailbreaking could “brick” the phone, meaning it becomes fully nonfunctional and you couldn’t restore the software to get it back up and running. These phone companies, Apple included, say that jailbreaking violates section 1201of the Digital Millennium Copyright Act.
In July 2010, the U.S. government approved some exemptions to the federal laws that permit jailbreaking of electronic devices. These exemptions are due to expire next month. The Electronic Frontier Foundation is working to get the exemptions renewed and get them expanded to cover tablets as well. If you’d like to let your representative know and urge them to renew the exceptions you can head to the Electronic Frontier Foundations website here and submit a letter.
Unless you know what you’re doing I wouldn’t recommend jailbreaking your device, since the large majority of people don’t need system-level access. I also do not condone jailbreaking for the purpose of pirating software; it’s actions like that that prevent people from doing legitimate, legal, activities on their iDevice.