Since the device's earliest days, users who chafed at Apple's draconian device restrictions have hacked their handsets to enable extra functionality, like access to 3rd party app stores with content that Apple refused to approve. Apple had claimed the process was illegal under copyright law.
But now an exemption has been created in the US that allows the legal breaking of DRM for: "Computer programs that enable wireless telephone handsets to execute software applications, where circumvention is accomplished for the sole purpose of enabling interoperability of such applications, when they have been lawfully obtained, with computer programs on the telephone handset."
The US Copyright Office explained the ruling by adding: "The user is not engaging in any commercial exploitation of the firmware. At least not when the jail-breaking is done for the user's own private use of the device."
Apple, for its part, has sniffily responded to Cult of Mac, saying: "Apple’s goal has always been to insure that our customers have a great experience with their iPhone and we know that jailbreaking can severely degrade the experience. As we’ve said before, the vast majority of customers do not jailbreak their iPhones as this can violate the warranty and can cause the iPhone to become unstable and not work reliably."
So what about Britain? Over here we have a far more tangled set of rules and regulations, thanks to the intervention of the European Union. The relevant EU directive essentially says that breaking "technical protection" (i.e. DRM) on software is fine, as long as you're not doing it for the purposes of infringing copyright (i.e. playing pirated games).
But that's Europe. In the UK, we have to ratify all of these EU directives before they become law, so the British lawmakers transposed the EU directive into British law, in the "Copyright and Related Rights Regulations 2003". That says essentially the same thing -- that it's okay to break these "technical measures" for interoperability reasons, but not for the purposes of infringing copyright.
