First step: Replace original recovery with ClockWorkmod Recovery
1. Download ClockWorkMod Recovery
2. Put the device in download mode (Power+Vol Up) and connect to PC,
and the PC will recognize the device as Removable Disc/Storage open it and you will find FIH > Image folder and select recovery.img, copy it anywhere to your PC as backup just in case if anything go wrong
3. Replace recovery.img in 'image' folder with recovery.img inside the Clockworkmod Recovery v220.127.116.11 you download and extracted earlier
4. Disconnect device from PC, open up the battery and reboot.
Second step (DO FIRST STEP FIRST): Rooting the phone
1. Download Su 18.104.22.168 signed.zip and put it in sdcard (but don't put it in any folder)
2. Put the device in recovery mode (Power+Vol Up & Vol Down)
3. Select "install zip from sdcard" and select "Choose zip from sdcard" and search for 'Su 22.214.171.124 signed.zip' and click install.
4. Select "back" and click "reboot system now"
Visit here read more info and download some files needed to root :)
actually this rooting tutorial is a repost from Paarkhi in xda-developers. Hope it helps you a lot, happy rooting :)) anyway do it at your own RISK. :)