Nowadays we have several cultural spaces accessible in the Internet. These synthetic worlds mix different medias (text, audio, image, video) and attractive user interface resources (as 3D ones). Not closed to presentation environments these applications offer to user other facilities: personalization, interactive views, additional information and communication tools. In this paper we describes a multi-agent architecture used to enhance 3D media spaces assistance. Our proposal is based on a 3D environment where users are represented by avatars. Each avatar has a personal agent that captures all the relevant user actions. We also have other types of agents, which are responsible for providing communication services. Also, we present a case study showing how these concepts were implemented in the ICSpace (Internet Cultural Space) environment.