In this paper we present our vision, and discuss the main research problems along with prospective solutions, on the evaluation of queries over data available and processable through services. In particular, we address queries in dynamic environments concerning aspects such as mobility and continuous data. These queries entail the potential of offering users ubiquitous access to relevant information in the form of value-added services. The core of our proposed approach, lies in the development of a services coordination framework complemented with proven traditional query processing techniques adapted to service-based environments. Thus, we derive the blueprint for an efficient solution for query evaluation in service-based contexts and their related application areas.