The main point is it's reckless to cut up a good pair of headphones, even if you have superb soldering skills, and what happens if you get a new pair of headphones?
This instructable will fill the void that I found on the internet with a short and simple headset hack, adding a 3.5mm jack to your mic/action button [iphone] headset.
What you will need:
1 Headset - needs to have the mic before the individual wires split - none of the kind with the mic on one side or the other
1 solderable jack - found mine at Radioshack
Time: ~20 minutes
Step 1: Cut and Strip
Strip the wires, but be quite attentive as the pair of internal wires are easy to damage. As shown in the picture, I stripped about 1.3cm (.5in) from the end, which is necessary, to be able to reach the solder points inside the jack.