What is rooting?
Android rooting is the process of allowing users of smartphones, tablets, and other devices running the Android mobile operating system to attain privileged control (known as "root access") within Android's subsystem.
Rooting is often performed with the goal of overcoming limitations that carriers and hardware manufacturers put on some devices, resulting in the ability to alter or replace system applications and settings, run specialized apps that require administrator-level permissions, or perform other operations that are otherwise inaccessible to a normal Android user. On Android, rooting can also facilitate the complete removal and replacement of the device's operating system, usually with a more recent release of its current operating system.
As Android was derived from the Linux kernel, rooting an Android device is similar in practice to accessing administrative permissions on Linux or any other Unix-like operating system such as FreeBSD or OS X.
I wan't to update to jellybean, how?
1). Can i root my phone?
If you are running ICS by default see this:
If you are running JB by default:
2a). What can i benefit from rooting my device?
Apart from mentioned above you can flash custom ROMs based on your choice.
2b). Is there a downside to rooting?
Yes, you may loose warranty if you damage your device by rooting.
3). What is ROM?
ROM is the whole system on your phone just like windows/mac os/ubuntu on PC.
4.). What is CWM and Custom ROM?
CWM and TWRP are recovery, in recovery mode you can flash new ROMs backup existing or factory reset etc. Custom ROM are Custom OS based on existing sources modified for better performance and reliablity.
5). What is this Stoc ROM/CM/AOKP/PA/PAC your talking about?
Stock ROM is pre-installed OS
CM is short for CyanogenMod, CM gives its user vanilla android experience (which is only present in nexus devices) at the same time more options and customization available there are 4 versions so far CM6(not available for explorer)(froyo 2.2.x),CM7(Gingerbread 2.3.x),CM9(Ice Cream Sandwich 4.0.x)and CM10(Jellybean 4.1- 4.2)
AOKP is short for Android Open Kang Project, AOKP brings user MORE goodies than CM gives and it also gives the user Vanilla android experience.
PA is Short for Paranoid Android, Also like CM but it gives you unique Tablet UI (phone will look like a tablet) for your device even though it's just a phone.
PAC is combined PA, AOKP, CM. It gives the combined features of the 3
6). How to install one of this rom ?
Look for the rom that you think you like in android development section and follow the instruction given by the developer.
7). So which of them is the best?
Try them all and don't compare roms people have their own preferences. when you compare roms some devs may feel bad and leave this device for good.
Comparing ROMs is very rude and disrespecting to developers.