Several interesting research directions materialize through the convergence of mobile computing and service-oriented computing. As mobile devices keep getting smaller, cheaper and more sophisticated, their use is becoming a commodity. We envision future scenarios that involve mobile devices acting not only as requestors, but as providers of data as well. In order to hide the heterogeneous nature of web data, service-oriented architectures are adopted. Nevertheless, existing service discovery mechanisms usually focus on exact or semantic matching of static attributes, thus ignoring contextual parameters. We argue that context for mobile web services plays an important role in service discovery by increasing the precision and efficiency of the search. We explain our notion of context regarding mobile services and describe query evaluation, updating and merging of context-aware service directories.