It's a program on pc, you can download it here: http://forum.xda-developers.com/showthread.php?t=2317790
I'm guessing you don't know how to use it, so I'll explain what you need to do.
1. go to settings in your phone and open "about phone", there ...
Anyone else's device trying to encrypt itself after installing twrp?
Go back in to recovery, wipe internal storage, cache & dalvik. Should be fixed after a reboot.
Once your phone is unlocked, it will no longer be covered by LG warranty.
Actually you only void warranty on software, hardware defects will still be covered.
Do we know if AT&T is using Qi?
They are according to this:
I just ordered a qi sticker on ebay for us $8.80 incl shipping (I unfortunately cant post links yet)
I'll report here once it arrives