This instructable tells you how to make your LG phone charge from a USB port using a spare wall charger.
Step 1: Getting Started
Look at the lable on your AC charger to make sure that the output is the same as a USB port(5v, 500mA). Take your wall charger and cut off the plug that goes into your phone. Then cut the USB cable to the desired length.
Step 2: Sodering
Cut off the outside of the usb wire then strip the positive and negative wires inside the cable. Take apart the plug and cut off and pull out the wire that connects it to the wall plug. Then push the USB wire into the hole were the wire you just took out was. Soder the USB wires and the Plug wires together and tape the exposed metal to prevent shorting. Lastly reasemble the plug.
Step 3: Finished Project
Your finished project might look like this. Mine works great and I've been using it ever since. Enjoy!
Step 4: Further Development
Rather than throwing away the rest of your wall charger you could SOLDER a female USB port to the curcut bord so that you can still use the USB charging cable you just made with you wall charger. This is further explained in this Instructable