Federal Communications Commission (FCC) mandates locating wireless phones that are in an emergency 911 call and many technologies were proposed and developed to meet that requirement. We review these techniques here because geolocation will have an even greater future role as a basis for value-added services and applications that integrate positioning and wireless multimedia. We explore in more detail one of the geolocation technologies, Assisted GPS, which has exceptional accuracy and cost-effectiveness. We also show how the SAMPS (System Assisted Mobile Positioning through Satellite) geolocation standard for TDMA wireless networks, based on assisted GPS, enables positioning-based services and enhances the performance of GPS receivers built into wireless handsets.