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.
Sn0wBreeze is a jailbreak tool that only works for Windows. The following guide will help you to perform tethered jailbreak for iOS 4.3 on iPhone 4, 3GS, iPod Touch 4G, 3G, iPad 1 using Sn0wBreeze 2.3 b1 (iPad 2 is not supported). Do not upgrade your iDevice to iOS 4.3 if you rely on unlock.