The aim of this paper is to present SPIN, an interactive and integrated software environment for scientific computation. The main goal of SPIN is to allow the access to remote computational and storage resources in an easy to use and transparent way from the user's point of view. This environment, based on a multi-tier architecture, has been developed following a state of the art software engineering process which incorporates the CORBA standard (Common Object Request Broker Architecture) the PAC-Amodeus model, (a multi-agent based model for interactive systems architecture) and the Unified Process (UP) to guide the whole life-cycle of the project.