What is iPhone Jailbreak
Jailbreaking : iPhone OS uses two partitions – first on is the media partition and second one is the operating system partition. Music, movies, contacts, App Store apps etc. are stored on the media partition. This partition is usually the size of your iPhone’s memory capacity, minus 500-600MB for the OS partition. Because of the way that Apple have set up the iPhone OS, we can not do any hacking in this easily accessible partition. To hack the device, we must get into the OS partition. The OS partition, the space on the iPhone that Apple has locked us out of, is where the jailbreak lies.
Jailbreaking is a process that allows iPhone and iPod Touch users to run unofficial code on their devices. Once you jailbreaked your iPhone you are able to download many applications, mods and hacks which are unavailable through the App Store but available via unofficial installers such as Cydia and Icy. Some of popular Cydia, Icy advantages are as on >> Winterboard (To install Themes), SBSettings (Faster Method to Manage iPhone Settings), Tricker3G (For running WiFi only App on 3G or EDGE), Cycorder (Video Recorder for iPhone 2G, 3G) and lots more.