Wash the area around the emblem well with warm soapy water; this will prevent scratches later on.
Apply heat with a hair dryer until the emblem is fairly warm to the touch, this loosens up the glue.
Use a plastic spatula or flossing wire to slowly begin breaking loose the glue bonding your emblem to the car.
Remove the emblem from the car entirely. Moving slow will usually help the glue pull away as well leaving less work later on.
Remove any left over glue with a goo removal product and a little elbow grease, but will be worth keeping the heat on . and again wash the area...