Go to radioshack, look for a 1/4" Male to 1/8" Female connector. Most Mic's (like the ones I have) are mini-jack, being the 0.135 inch width (or close to it). You need to buy the adapter. All together, the VRU: $1: Salvation Army, Headset: Free: Online Offer, Jack Adapter: $5: RadioShack.
Again, I prefer to use my "custom" mic more than the "original" as the "custom" mic is more of a headset instead of a mic on a stand.