The iDevices (iPhone, iPod touch and iPad) hacking that allows users to access to the entire Unix filesystem is called jailbreak or Jailbreaking is a process that gives a user read/write access to locked OS files on iDevices. Jailbreaking gives a user complete control over iPhone (and other iDevices) including customizing it and 3rd party apps installation. Jailbreaking is a hack to gains access to areas of the iPhone, iPod touch or iPad that users are not supposed to mess with. After that users can install 3rd party cool programs or unlock the handset for use with another cellular network. Lets talk about jailbreaking in detail.
Comex, the developer of JailbreakMe 3.0 is about to release the iPad 2 jailbreak. One of the beta testers of iPad 2 jailbreak via JailbreakMe has leaked the jailbreak. He was able to jailbreak iPad 2 by downloading a pdf file in mobile Safari on the iPad 2 which contains the exploit developed by Comex and will jailbreak your iPad 2, allowing you to access Cydia. This iPad 2 jailbreak is currently in beta version and will contain few bugs and will only work on WiFi models of the iPad 2. Safari has been reported to crash on your iPad 2 if you use this method. Better approach is to wait for Comex final official release.
Jailbreak iOS 4.3.3, Jailbreak iOS 4.2.8 using PwnageTool 4.3.3, Sn0wbreeze 2.7 and Redsn0w. Following are complete guides and tutorials to jailbreak iPhone, iPad and iPod touch.