A new tutorial explaining how to add geoprocessing to Web applications became available today in the ArcGIS Server Web-based help. This tutorial walks you through the process of building a model and creating a map to display the model inputs and results. It then shows how to publish both the map and the model as services and add them to a Web Mapping Application.
To complete the tutorial, you need a few simple GIS datasets and ArcGIS Server for the Microsoft .Net Framework. You also need access to ArcMap. Give it a try and leave us a comment about your experience!