In this article we showcase an agent-mediated B2C and B2B e-Marketplace. This e-Marketplace is part of the social and immersive 3D e-Tourism environment “Itchy Feet”. We give an overview of the framework that forms the basis of the e-Marketplace and show how it is used to create B2C-, B2B- and Virtual Organizations that are visualized in a 3D Virtual World. This interface provides users with an intuitive and easy way to interact with humans and software agents by means of a 3D Virtual World. The business logic is realized by autonomous software agents offering services to customers. The e-Marketplace is regulated by Electronic Institutions to ensure that all participants adhere to the rules of the market. The article is concluded with a detailed discussion on bridging the gaps between Multi-Agent Systems and 3D Virtual Worlds and the preliminary results of a conducted usability study of “Itchy Feet”.