I have a Creative Fatal1ty gaming headset:
As you can see the mic is removable, I never really needed the mic but I would like it now but it doesn't work, I use onboard sound. When i'm listening to music or something, the bars go up and down on the speakers (or headphones) as so does the microphone volume, like it is coming directly from the PC not from my mouth. It uses a 3.5mm jack so I tried plugging it into the pink slot itself and it works but it's too far away for me to use. Oh and the mic is switched on on the volume control bit.