TOOLS NEEDED: soldering iron, wire strippers(your teeth...jk), screwdriver
ITEMS NEEDED: long extension cable for headphones, you will be cutting one end off.
if you can find in your garage or somewhere a headphone (male) coupling with an open end, then you are lucky and you don't have to buy one. I just got mine from radioshack its quality and the wires are big and easy to solder.
Sometimes headphone wires will be small and enamel-coated (instead of insulated rubber) and they can be tricky so don't use them unless you are zuper awezome.
SKILLS REQ'D : soldering, understanding your own car's components, understanding basic radio components and being comfortable altering them.
I have pictures from my radio, and you can see how it was done from the pictures I took after I finished and was putting it back together.
It depends on which radio you have, I have the A51813 well thats what it says on the outside
Model No. 816120-02430
Ref No. CQ-JS7460X
Serial No. MX658147