The present document is part 14 of the Stage 3 Parlay X Web Services specification for Open Service Access (OSA). The OSA specifications define an architecture that enables application developers to make use of network functionality through an open standardized interface@ i.e. the OSA APIs. The present document specifies the Presence Web Service. The following are defined here: ? Name spaces. ? Sequence diagrams. ? Data definitions. ? Interface specification plus detailed method descriptions. ? Fault definitions. ? Service Policies. ? WSDL Description of the interfaces.