This paper presents the development of the "Entertainment Guide", a 3G location-based entertainment guide application for the outdoor environment. The focus of this research study is on the software support for location-based applications, especially designed for 3G mobile networks. Contrary to the majority of the available LBS applications, the current study deals with the design and the implementation of a real 3G LBS application, offering to mobile users added-value services, such as high quality mobile multimedia location-aware content on high-data-rate wireless channels. In this paper we describe the Entertainment Guide system and discuss the processes involved in the development of this 3G LBS application (location-based service supply chain and system architecture).