In this article, the author explains how to design and implement Web- based interfaces, known as portlets, to provide end-user interfaces for using grid services. He explains the open source portal framework GridSphere and provides code examples of portlets in the GridSphere model. The article also explains the integration of OGSA-based grid services and GridSphere, and it includes a grid portlet example that shows how to write a portlet to access a sample OGSA counter service.