Download Click

            "Rooting is a process that allows users of cellphones and other devices running the Android operating system to attain privileged control (known as "root access") within Androids Linux subsystem, overcoming limitations that the carriers and manufacturers put on such phones."

Warning:
First off, let me start by saying that if you dont think you need rooting, dont root.
It can be dangerous if done wrong, so be sure you know what youre doing.
With that out of the way, lets get going then.
Rooting voids Warranty!
[ but we can unroot our device before submitting to service center... ;-) ] 

Actual Process:
We can use SuperOneClick or any of the following softwares for rooting our W8

• Flash tool,Universal Androot ,Recovery Flasher,Easy Root,Unrevoked...use google to find them.

1. Download SuperOneClick.
2. On your phone, go to Settings -> Applications and enable Unknown Sources.
3. Next, go to Settings -> Applications -> Development and enable USB debugging.
4. You also need the proper USB drivers.(Install PC Companion to get the drivers.) To check if you have them, start SuperOneClick.exe and click Driver Check. If the driver check fails, update your phone with PC Companion.
5. Now, connect your USB cable from your W8 to your computer. When connected it is VERY IMPORTANT to select CHARGE PHONE.
6. Start SuperOneClick.exe and just click ROOT. Everything should go normally. You might get a message asking you if your OS is 2.0 or higher, just go ahead and click Yes.
7. You should now be rooted! :)

Disclaimer: I wont be responsible if u damage your phone!