Smartphones have come a long way over the past 10 years—from containing a simple database of calendar entries and contacts to including a digital camera, digital compass, GPS, and thousands of apps available with the touch of a button on the screen. People like smartphones for many reasons, particularly because of their mobility, friendly user interface, large number of useful applications, interactive games, and higher bandwidth with the help of 3G networks. From a technical point of view, the fundamental reason behind the popularity of smartphones is that they are not only a communications device, but also provide a powerful sensing and computing platform. A growing number of computing tasks previously executed on PCs are now being performed on smartphones. Because of all this, smartphones are increasingly attracting attention from researchers, with research efforts in mobile media streaming, video retargeting, location-based systems, and mobile vision systems, among others. PositionIt, a mobile media-based remote target-localization and tracking system, is one part of a comprehensive system that uses networked smartphones to localize a remote target of interest by fusing data sensed by microphones, cameras, and other embedded sensors.