In recent years, mobile guides have been object of a widespread interest. They allow tourists, businessmen and occasional users to access many different services from portable lightweight devices, such as PDAs or high-end mobile phones. In this project, we explore the use of 3D graphics in a location-aware mobile guide to visualize the area the user is currently navigating, making it easier for the user to obtain the desired information about her objects of interests. We also propose a preference-based search tool aimed at supporting users in the search of points of interest in a geographic area by combining dynamic queries with a visualization of the degree of satisfaction of constraints set by the user. Moreover, we are designing and comparing different ways of providing navigation guidance through a mobile guide, combining visual and audio directions during guided city tours.