This paper presents a particular aspect of the architecture of Collaborator, a software system that provides enterprise users with a shared workspace to support the activities of virtual teams. Collaborator exploits the seamless integration of everyday Web technologies with agents to promote flexibility in the interaction between users. In this paper we concentrate on the agent subsystem of Collaborator, and we show the architecture of this multiagent system and the functionality that it provides. In particular, we present the roles that agenst play in the overall system (personal agents and session manager agent), and we detail on how personal agents are used to (i) manage the calendar of users; (ii) negotiate and classify meetings; and (iii) learn the preferences of users.