PDAs can be used to provide their users with various functions. One such function is the ability to contact other users who are stored in the PDA as contacts, for example by telephone of text message. The decision as to whether or not a particular user should be contacted may be influenced by the location of that user. For example, if a contact is nearby, then it may be more likely that the user of the PDA would want to contact them. The present invention provides a PDA on which the location of one or more contacts can be displayed. Furthermore, the location of a particular contact can be shown on a map on the screen of the PDA simply by tilting the PDA through a predetermined angle about a horizontal axis. Thus, the map can be displayed in an intuitive and straightforward manner.