A sizable amount of data on the Web is currently available via Web APIs that expose data in formats such as JSON or XML. Combining data from different APIs and data sources requires glue code which is typically not shared and hence not reused. We propose Linked Data Services (LIDS), a general, formalised approach for integrating data-providing services with Linked Data, a popular mechanism for data publishing which facilitates data integration and allows for decentralised publishing. We present conventions for service access interfaces that conform to Linked Data principles, and an abstract lightweight service description formalism. We develop algorithms that use LIDS descriptions to automatically create links between services and existing data sets. To evaluate our approach, we realise LIDS wrappers and LIDS descriptions for existing services and measure performance and effectiveness of an automatic interlinking algorithm over multiple billions of triples.