Jailbreaking your iPhone or iTouch is when you hack the filesystem by means of an exploit/flaw in the firmware. The end result of jailbreaking is that the user has direct access to the root partition of the iDevice, allowing for the installation of unauthorized third-party apps. There are 4 main programs used for to jailbreak an iPhone or iTouch: QuickPwn, PwnageTool, iFreedom, and Redsn0w.

Unlocking is the process of tricking the iPhone’s baseband to allow the user to use an unauthorized SIM card with the iPhone. The end result is an iPhone that may be used on any network that provides its customers with a SIM card, most popularly, T-Mobile.

iPhone 2G is the original iPhone released on June 29, 2007. Its main advantage over its successor, the iPhone 3G, is that a hardware exploit has been found in the iPhone 2G bootloader, which means that no matter how much Apple attempts to prevent unlocking on the iPhone 2G, they will ultimately lose because the only way to fix the hardware exploit is to replace physical components of the iPhone 2G.

iPhone 3G is the second generation of the iPhone and was released on July 11, 2008. It biggest advantage over its predecessor is that it supports 3G networks, which provides the iPhone 3G with significantly faster internet. The downside to the iPhone 3G is that no one has found any exploits in its bootloader or baseband, so there is no software unlock yet. There is, however, a simple hardware unlock using a Turbo SIM.

iTouch 1g is the first generation of the iTouch. It is for the most part an iPhone without the phone capabilities or the camera. There’s really not that much of a difference besides that. Hardware wise, its pretty different because the iTouch can have a larger hard drive than the iPhone and the iTouch lacks the cellular and bluetooth connections and the camera. Software wise, it is very similar to the iPhone and even shares the same build version now. The main difference software wise is that the iTouch does not have the Phone, text messaging, or camera apps because it doesn’t have the necessary hardware.

iTouch 2g is the second generation of the iTouch. While it still lacks some useful hardware, like a camera, its hardware has been updated to be closer to that of the iPhone. It has volume buttons on the side of it, external speakers like the iPhone’s, a faster processor, bluetooth hardware (the firmware doesn’t use it yet), and more. The only downside to the iTouch 2g is that Apple fixed a hardware exploit that allowed jailbraking on the iTouch 1g. Instead of using QuickPwn, iTouch 2g owners must use a program called redsn0w instead.