Open source software is growing in the market, and increasingly preferred toclosed software for the increased flexibility free software provides. As aresult of this more and more businesses are trying to enter this market andprofit from open source software.Consultancy agencies targeting the public sector are in demand of expertise andproducts released as open source. As this is a new field for many companies,studies are needed on how to approach these markets with a high chance ofsuccess with regards to business models and the technological benefits thatopen source software may provide. The problem description raises two researchquestions:* Is authoring of open source software a viable business idea for consultancy agencies?* How should software be released as open source?This thesis presents two main contributions for answering the research questions.The first is a set of guidelines and techniques for estimating the business viability of aof open source software venture. The second is some best practices for authoring and releasingopen source by observing the successful projects that already exists.In addition to these theoretical parts of the thesis, a system for analyzing andgenerating XSLT-transformations for OpenFEIDE is presented.