Jailbreaking an iPhone, iPod Touch or iPad allows a user to install apps from places other than the Apple app store. Unlocking an iPhone enables it to be used with any wireless carrier by removing the "lock" that forces it to be used only with the carrier that originally sold the phone.
What it means
Apple tightly controls the ecosystem of apps that run on the hundreds of millions of iOS devices sold. Owners of iOS devices (iPhones, iPads, iPod Touch) can only install apps from Apple's app store. Although there are now hundreds of thousands of apps in Apple's app store, some critics have said this control over the device even after it has been sold hurts innovation and the consumer. However, Apple maintains that by restricting access to authorized apps only, it can ensure a measure of quality control and also protect users from their devices being hacked.
Jailbreaking is the process of removing these limitations imposed by Apple on these iOS devices it sells. It enables you to run “unauthorized” software that isn’t approved by Apple.
Several wireless carriers around the world, but most commonly in the United States, subsidize the cost of a new iPhone to consumers by binding them to a contract to use the services of the carrier, usually for 2 years. This allows a new phone to be purchased for only $200 instead of its regular "no-contract" retail price of about $650.
These iPhones are "locked" to only work on the telecom network of that specific wireless carrier. Unlocking is the process of removing this restriction and freeing up the phone to be used with any wireless network. Depending upon the model of the iPhone, there may be restrictions even after unlocking because phones that support only CDMA cannot be used on a GSM network. Unlocking allows the consumer to use a different wireless service without being forced to change her phone.
How to Jailbreak an iPhone or other iOS Device
Free desktop-based jailbreaking tools are easily available on the Internet. These can be used legally; however in certain cases you may lose the warranty on the product. Hackers such as @planetbeing, pod2g and  are well-known for their Jailbreaks.
Here's a list and history of popular jailbreaking software:
- In October 2007, JailbreakMe 1.0 (also called "AppSnapp") allowed people to jailbreak iPhone OS 1.1.1 on both the iPhone and iPod Touch, and it included Installer.app as a way to get software for the jailbroken device. Comex released JailbreakMe 3.0, a web-based tool for jailbreaking all devices on certain versions of iOS 4.3, including the iPad 2 for the first time (on iOS 4.3.3)
- iphone Dev Team released a version of PwnageTool in July 2008 to jailbreak the new iPhone 3G on iOS 2.0 as well as the iPod touch, including Cydia as the primary third-party installer for jailbroken software. They keep updating it.
- They released QuickPWN to jailbreak iOS 2.2 on iPhone and iPod touch, which also enabled certain functions disabled by Apple.
- After Apple released iOS 3.0, the Dev Team published redsn0w usable on Mac and Windows, and they keep updating it.
- Chronic Dev Team initially released greenpois0n in October 2010, a desktop-based tool for jailbreaking iOS 4.1and later iOS 4.2.1 on most devices including the Apple TV, as well as iOS 4.2.6 on CDMA (Verizon) iPhones
- The iPhone Dev Team, Chronic Dev Team, and pod2g collaborated to release Absinthe in January 2012, a desktop-based tool to jailbreak the iPhone 4S for the first time and the iPad 2 for the second time, on iOS 5.0.1 for both devices and also iOS 5.0 for iPhone 4S.
- An update on several tethered and untethered jailbreaks for iOS 6. As of this writing, iOS jailbreak had been achieved for iPhone 4, iPhone 3GS and iPod Touch, and a tethered jailbreak for the iPhone 5 had also been achieved, but required the user to have a $99 per year iOS developer account.
The following video demonstrates how to jailbreak a few Apple products:
How to Unlock an iPhone
One way to unlock the phone is to use software like iPhonelox but the preferred way is to work with your wireless carrier to unlock the phone "officially". You can do it yourself by going through the tutorials and community support forums available for the particular phone or network provider on the Internet.
If unlocking using software, the iPhone will have to jailbroken first to be able to install the unlocking software. Some providers ask you to pay to unlock your phone but they are not trustworthy so think twice before sending them your money.
When working with your wireless carrier to unlock your phone, there may be some eligibility requirements. For example, AT&T requires that the phone should not be under the binding contract. Sprint customers can request unlocking of their iPhones but only for international travel. Verizon sells iPhone 5 with the SIM slot unlocked by default.
Resources to help unlock iPhones
- Apple's article: About Unlocking
- AT&T's eligibility requirements for unlocking iPhones
- Request AT&T to unlock your phone
- Verizon iPhone 5 sold with their SIM-card slot unlocked by default
- Verizon iPhone unlock tutorial
Even after unlocking, the networks that a phone works on depends upon what networks are supported by the hardware. iPhone 5 supports both CDMA and GSM. Sprint and Verizon iPhones use CDMA; T-Mobile and AT&T use GSM. Most countries in the U.S. and Europe have GSM networks. iPhone 5 if sold for Sprint has its GSM SIM card slot locked even though Sprint does not use it. But when sold for Verizon, iPhone 5 has its SIM card unlocked by default. This is a good reason to choose Verizon over Sprint if unlocking is important to you. However, Verizon iPhones cannot use AT&T's faster LTE network. See iPhone LTE support for more info.