Recent advances in wireless data and real time communication have stimulated the need to allow mobile users to send multicast data by using secure and seamless connectivity to the global Internet and with one another without any compromise. IP multicast provides solutions to a broad range of services. For example e-learning courses, MPEG video, Videoconferencing, and White-boards etc. In all of these applications, IP multicasting conserves a huge amount of bandwidth by simultaneously sending the information to multiple recipients. The Mobile IP is the standard which supports mobility and provides two schemes for mobile users to receive multicast packets, either by using a tunnel from the home agent (home subscription) or by joining multicast groups in the foreign network (remote subscription). Both schemes are a compromise in terms of security and routing in order to support multicast in Mobile IP. The problem with the first scheme is that it uses non-optimal routing and latency increases as the mobile user starts moving away from the home network, the second scheme requires a multicast router in the foreign network and may suffer from frequent modifications in the multicast distribution tree each time the mobile user moves to a different foreign network. Also, the solutions provided for multicasting in mobile networks are not secure, and bogus users can easily intercept multicast packets by becoming a part of the multicast distribution tree. This thesis describes and discusses the research related to improving secure multicasting mechanism in Mobile IP with special reference to real time applications. It introduces Trusted Multicast Agents (TMA) to facilitate secure multicasting in Mobile IP. A trusted multicast agent is a secure and trusted multicast router that serves disjointed multiple foreign networks by sitting in the middle of the sender and receiver.