Sourced from http://forum.xda-developers.com/showthread.php?t=991668

Requirements:
Windows PC
LG Optimus V USB Serial Drivers

Download:
CDMA Workshop 3.6.0 Demo

Instructions:
  1. Turn on USB Debugging, and connect your phone to your PC.
  2. Open Device Manager.
  3. Ports > LGE Android Platform USB Serial Port > Properties > Port Settings > Advanced > COM port number
  4. Change the value to a port number below 10. (demo restriction of CDMA Workshop)
  5. Open CDMA Workshop
  6. Select the proper port from step 4. Hit "Connect."
  7. Under the "Security" tab, find "SPC/User Lock."
  8. Change the drop down menu to "LG method," and click "Read."
  9. Write down the number that appears in the box. This is your MSL code.

NOTE: If you don't see the port in Device Manager, turn off the phone and re-connect the USB. Windows should find the correct drivers. Leave the phone OFF as you follow the procedure.