1. A computer implemented method for performing an operation on a computer system in response to input received from a user, the method comprising: identifying a home position on a touch screen corresponding to the location of a first touch input; in response to said identifying step, displaying a virtual controller on the touch screen, wherein a portion of the virtual controller is located at the home position; and detecting movement of a second touch input along the touch screen relative to the home position, wherein the first touch input and second touch input are simultaneously in contact with the touch screen; and performing an operation in response to the detected movement of the second touch input.