AnswerBuy a good rat trap (Victor, for example) and bait it with peanut butter and oatmail.
If it's in your house: turn a carboard box (with flaps tucked inside) upside down over a flat piece of board. Set this in a corner of the room. Prop up box just a few inches with a stick that has a long sting attached. Chase chipmunk into the corner and pull the string so that the box drops over him. Carry out the box and the board outdoors. This really works!