Hi,
its a bit of a chew on but doable.
first you need to open up the mic part, an old credit card or similar is your friend here.
should just split in half.
then underneath the wire there is a small x screw to remove and thats the mic part open, the sync switch and led numbers will come out here.
now take off the ear loop and remoce the tri-wing screws you can bodge them out with a very small x driver if need be.
now again with the old credit card you need to carefully seperate the ear piece. when you seperate it you need to slowly and carefully remove the speaker and the battery from the cover.
there is now 2 more screws in the grey plastic holding the last bit of the white plastic together, remove these then unclip the circuit board.
thats you done mate.
be sure to check the voltage needed for your led's because its only a small battery and i dont know what colour leds it will power.
check out my headset below, enjoy.
Custom black Xbox 360 wireless headset