It's just an extended fuse. So one fuse becomes two fuses, with a wire to connect your new component - check here (add-a-circuit):
http://www.parts-express.com/pe/show...ource=googleps
You pull out the old fuse, put the fuse in the add-a-circuit, put one more fuse for the new component, and connect the wire from add-a-circuit to your new component.