My dock connector had become "touchy," with the internal contact loose. It would often lose connection from chargers or music docks.
The repair was tricky and I ran into two problems. 1: The 00 Philips that I ordered from ifixit had such a rounded, dull point that it was useless for any of the 6 internal screws that I had to remove. I luckily was able to use a very small eyeglasses repair flathead screwdriver I had to remove these screws. 2. There is a small rubber "microphone holder" that has to be removed (see step 19 in the ifixit guide). This little rubber piece is connected to the dock connector that will be coming out of the phone. The big problem was that the dock connector replacement sent my ifixit DID NOT have the rubber microphone holder. So, I had to carefully remove it from the old dock connector and connect it to the new one. This was very difficult and ifixit's otherwise EXCELLENT guide did not point this out at all.
iFixit's guide is excellent. Use it, being sure to look at giant size photos when they are available. BUT - be sure to pay close attention as you go as the guide doesn't cover 100% (small criticism here as the guide was about 99% complete). I recommend taking several close up pictures of the inside of the phone before you start taking things apart. They will no doubt come in handy when you are trying to put everything back and are just following the ifixit guide in reverse.