If you didn't get one with your Jeep you can buy one from just about any hardware/auto-parts store. Just ask for a T40 Torx driver. Note that the door takes a T50 Torx, so if you're going to buy one you might as well buy them both if you're ever going to take the doors off.
Remove the 6 Torx bolts and store them in the center console or the rear compartment. I keep mine in a plastic baggy with the Torx driver so they're all together.
