This research examined the requirements for multiple travelers to request a local, medium-distance, national, or international itinerary plan from any node of a public transport journey planner system using timetable or schedule data from numerous public transport companies and modes. It was resolved that a four-tier, client-server architecture and a distributed data service would best meet these requirements, using the Internet to exchange trip schedule data according to an agreed JourneyWeb protocol based on extended markup language. The JourneyWeb protocol is explained, and the field characteristics and attributes used in mutual data interrogation between itinerary planning services, allowing the web of services to expand, are defined. Successive iterations of a prototype system, first between two counties and then expanded to include a larger geographic area, demonstrate progress to date using real schedule data.