This paper presents a survey on current trends in several technologies related to avatars and introduces a new solution for interoperability of avatars in Virtual Worlds. A short examination of several standards, recommendations, markup languages and VWs presentation definitions addressing different aspects of avatars are provided. As a result of this analysis, a new standard, called MPEG-V, aiming to provide an interchange format for virtual worlds is presented.Providing the container of avatar properties/capabilities is the vision of MPEGV. By its descriptive format it aims to facilitate the deployment of VW recognizing that their success depends on maintaining acceptable development cost and one mechanism in doing so consists in ensuring interoperability between them at least at the level of avatars