Summarize this article:

Press the Power button at the top to shut your phone off. On the LG VS950, it is on the left side. Use a SIM card from the other network you want to use, like AT&T or Sprint, for instance. You can also use international or foreign SIM cards. Once it’s on, wait for it to finish loading. Instead of the usual home screen, a different screen will be displayed where you will be asked to enter a code. Once you’re done, press “Okay” to enter the code. A confirmation message will then be displayed on the screen telling you that you’ve successfully unlocked the phone.

Summary:
Turn off your phone. Open the SIM card slot. Insert a SIM card from a different network. Switch on your phone. Type in the unlock code using the on-screen keypad.