Interface control using motion of a mobile device

The invention relates to improved user interfaces for hand held computing devices such as mobile phones. It describes a method of controlling the location of a pointer on a two or three dimensional desktop using a handheld mobile computing device having a camera facing the user. The camera captures an image of the user's face detects a relative orientation of the handheld mobile computing device and the user's face and controls the pointer location on the two or three dimensional desktop responsive to the detected orientation. Preferably the pointer is represented on a user-facing display together with a portion of the desktop at the pointer location. The portion displayed is changed together with the detected orientation to give the impression that the desktop is located behind the display, such that the display forms a portal through which the user looks at the desktop.