My iPhone 4 all of sudden would not recognize the wall charger. The battery slowing drained and the phone became useless. Verizon told us it was junk and that we needed a new phone. We replaced the battery and the Dock Connector (which was the culprit), and it works as good as new!
The repair process went great! Great family project.
Pay attention to all of the small screws. I hate that part, but still managed to get it all back together.