Life-scientific Web services are increasingly available and diverse. Their semantic interoperability is crucial to enable automated workflow construction and efficient searching for the right service. At the same time, smooth programmatic access must be possible with all the main programming, scripting, or workflow languages. This tutorial gave an introduction to the "SAWSDL":http://www.w3.org/standards/techs/sawsdl#w3c_all standard for semantic annotation of Web services and XML Schemas; the "EDAM":http://edamontology.sourceforge.net ontology for describing bioinformatics tools; and "BioXSD":http://bioxsd.org as a canonical data model for bioinformatics Web services. EDAM (EMBRACE Data And Methods) defines terms for annotating the service scope, functions and the types of input and output data. BioXSD defines an exchange format for common bioinformatics data types which are not covered by specialised standards. BioXSD is annotated with EDAM terms, thus serving as an example of XML Schema annotation and as a set of ready-made building blocks for Semantic Web service interfaces. The practical, combined approach of XML Schema and SAWSDL annotation (recommended by the _EMBRACE_ FP6 project) ensures maximum interoperability with both the Semantic Web and the common SOAP and XML libraries. Tutorial included a hands-on exercise session of editing and annotationg a WSDL file(s).