The Carnegie Mellon Communicator project has developed a telephone-based spoken language dialog system that allows users to interactively create travel itineraries using live information from the Web. The system is built from existing open source components, including the Carnegie Mellon Sphinx recognizer, the Carnegie Mellon / Colorado Phoenix parser and the Festival text-to-speech system. To this the Communicator project has added the Agenda dialog manager to support flexible mixed-initiative dialog and we have also developed a stochastic language generator as well as other components to assemble a complete set of components for dialog system implementation. Communicator serves as a platform for research in language and dialog and as a base for developing spoken language systems for new domains.