Service discovery and its automation are some of the key features that a large scale, open distributed system must provide so that clients and users may take advantage of shared resources. Most actual distributed systems are built with several middleware applications developed by using grid and web service technologies that allow an infrastructure to be implemented where users work as if they were in a local system. The paper, starting from the work done within grid projects in which the INAF Institute was involved, examines issues encountered and solutions proposed in the optics of sharing and thus using web resources such as web services in a specific grid system. By guaranteeing the efficient use of such resources, different discovery mechanisms, developed within grid and web service areas, have been evaluated. The results show the necessity of an appropriate resources' description in terms of the information data model, protocol and search tools that could integrate semantic t...