How to Use Root on Androidby Shawn Farner
Gaining "Root" access to your Android smartphone means that you have complete, system-level access to all of the functionality the Android operating system and your phone can provide. Access to certain hardware or software features can be blocked from use by an application unless that application is run on a rooted device. If you've enabled "root" access on your phone, you gain the ability to perform actions and use features that you might not otherwise be able to.
Install custom ROMs on your Android smartphone. By gaining root, you can ultimately install a custom recovery application, which in turn lets you use Android builds developed by the Android development community. These ROMs, while not always stable, usually add features or performance upgrades when compared to stock ROMs offered by carriers. For example, some ROM builds strip out all of the pre-installed carrier software, giving you more app installation space and allowing your phone to run more smoothly.
Overclock your Android phone's processor. Overclocking is not a feature built in to the Android operating system, but it can be added if you have root access and an overclocking application installed that is compatible with your device. By overclocking, you can make your phone's processor work faster than it does by default.
Enable features that would otherwise be unavailable for your phone. When a new Android device comes out, it will sometimes have an exclusive feature included with its Android OS that other phones running Android won't get until later. If you have root access, you can often install and enable this feature before those who don't have root access. For example, when "Live Wallpapers" first appeared as a feature, it was only available on the Nexus One handset. But rooted users of other phones soon got the feature working on their own devices. A similar example is that of WiFi tethering. This feature is sometimes disabled on certain Android phones, but a rooted user can get the feature working.