Jailbreaking means that Apple users can ‘liberate’ their phones and iPads from the restrictions of Apple. Apple only allows apps and programs that are approved by it, on its users’ devices. Any third-party app is not allowed on the mobile devices. With jailbreaking, users can access content that was previously inaccessible, and download whatever they want on their phones.
The downside is that this act violates the terms and conditions of Apple and thus, the warranty of the devices become void. This can prove to be drastic if a say, $500 iPad, in the process of being jailbroken, ceases to function. Anything that can go wrong with the device will be the responsibility of the user and thus, some heavy losses can occur. Also, the jailbroken devices do not get updates automatically from Apple. Users of jailbroken devices have to wait for hackers to provide them with the unofficial version of Apple updates. Thus, it is advisable to perform jailbreaking only and only if there is some specific need to access third-party apps and programs for the devices.
The jailbreak tool for the iPhone 4S and the iPad 2 is called Absinthe and can be downloaded on the Mac. The problem has been the user traffic that is slowing down the website. Other than that, the instructions for the hack can be obtained from iPhone Dev-Team Blog.