I have to give props to mysticalvibes, whose instrucable helped me out when I made my headset.
I had all this stuff at home already, so essentially it cost me nothing, but you can get this stuff pretty cheap of ebay or something.
What You'll Need:
-Xbox wired headset
-Pair of Headphones
-Soldering iron and solder
-Electrical tape/Heat shrink
-Phillips head screwdriver
Step 1: Disassemble The Xbox Headset
Start by taking off the foam ear cover on the headset so you can remove the speaker. The speaker easily comes off by pressing in the three (3) black tabs.
You will need to desolder the wires from the speaker so it can be completely removed.
You can now remove the heat shrink from the microphone wires and desolder them.
The boom can be removed by undoing the screw. You can also remove the cord by undoing the knot and pulling it through the rubber bit.