One of the factors that limits scientists from fully adopting e-Science technologies and infrastructure to advance their work is the technical knowledge needed to specify and execute scientific workflows. In this paper we introduce WDO-It!, a scientist-centered tool that facilitates the scientist's task of encoding discipline knowledge in the form of workflow-driven ontologies (WDOs) and presenting process knowledge in the form of model-based workflows (MBWs). The goal of WDO-It! is to facilitate the adoption of e-Science technologies and infrastructures by allowing scientist to encode their discipline knowledge and process knowledge with minimal assistance from technologists. MBWs have demonstrated potential to facilitate knowledge understanding and transfer of key scientific processes for a wide range of people, including students. An experimental version of WDO-It! has been developed as a proof of concept and scientists are using the tool to develop experimental WDOs and MBWs for several scientific disciplines.