Convergence of information and telecommunication networks leading to integration of voice, data and video services will bring new opportunities for users as well as service providers. With a growing number of services available on the market, dynamic discovery of services, their composition, selection, mediation as well as execution will be required. In this paper we show how voice and data services can be seamlessly integrated using existing client as well as server VoIP systems based on a widely used SIP signaling protocol and newly emerging technologies in Semantic Web Services. Within particular use case scenario, we describe all phases of the call set-up between two call participants. We show how Semantic Web Services technology can facilitate dynamic and optimal integration of voice and data services with different characteristics while at the same time conforming to users? needs and preferences.