Things to Do Before Proceeding
1. Battery is full.
2. Have the *.apk files of your favorite apps on PC if possible. Less hassle to find and install back afterwards.
3. Make sure LG Phone USB driver is PROPERLY INSTALLED.
4. I will not be held responsible should anything undesirable happen to your phone.

For the rooting,,just use the gingerbread.apk root app..
go here n follow de step Link

after dat
Flashing with Custom ROMs
##Things to download## (I'm using CyanogenMod as example)
1. Download CyanogenMod.
2. Download Terminal Emulator and install on phone.
3. Download Custom Recovery Tool Imageand its Flash Image, and put them into SD root (the main folder of SD card). Remember, the *.img file, not the *.zip file.

##System Recovery and Flashing##
1. Load Terminal Emulator on phone.
2. Type "su" (without quotes) and press enter, the $ should now become #.
3. Type exactly what is in the spoiler, down right to capital letters and spacing. Line by line (rotate your phone horizontally for easy view).

and then..write dis correctly

*an error will appear when you register the 4th line, it's OK so leave it be.

4. Switch off the phone after completion. Now, reboot into recovery mode by pressing and holding power button, volume down button and home button. Use volume button as up and down keys, menu button as Enter/Yes.
5. Run Nand Backup External
6. Run Partition SD card. You must do each menu available step by step (the last step would be ext3 to ext4).
7. Run Wipe All, then reboot.
8. Connect the USB to your phone, transfer the .void ROM (zipfile) to SD root. Disconnect the USB cable, and reboot.
9. Boot into System Recovery again (power, low volume and home button).
10. Select Flash menu, choose the .void ROM, and initiate flashing.
11. Reboot, and this time it will take a while (around 5 minutes for first boot).
12. Should be running on .CyanogenMod (or any custom ROM) by now.