Designing web sites is a complex task. Ad-hoc rapid prototyping easily leads to unsatisfactory results, e.g. poor maintainability and extensibility. However, existing web design frameworks focus exclusively on data presentation: the development of specific functionalities is still achieved through low-level programming. In this paper we address this issue by describing our work on the integration of (semantic) web services into a web design framework, OntoWeaver. The resulting architecture, OntoWeaver-S, supports rapid prototyping of servicecentred data-intensive web sites, which allow access to remote web services. In particular, OntoWeaver-S is integrated with a comprehensive web service platform, IRS-II, for the specification, discovery, and execution of web services. Moreover, it employs a set of comprehensive site ontologies to model and represent all aspects of service-centred data-intensive web sites, and thus is able to offer high level support for the design and development p...