This paper presents the identification, design and implementation of a user interface to a brokerage system and the conceptual architecture and functional behaviour of an intelligent interaction agent that supports and enhances the interaction between the user and the system. The term interaction agent is used in order to describe a particular class of interface agents that function as intelligent personal assistants to users of a computer based system. The interaction agent provides assistance to the user in two contexts. On the user interface level, it assists users to comprehend and manipulate the user interface. On the domain of application level, it provides users with information and advice according to their preferences. This work is being carried out in the context of an ACTS (AC 221) project GAIA (Generic Architecture for Information Availability).