Dennis Byron's excellent post, 'Why Companies "Turn to Open Source Software"', rings many bells with me. Sometimes as implementation consultants (primarily using Microsoft business solutions), in our case, we are tempted to question whether we'd be better off implementing open source code with clients – potentially more to spend with us, as theconsultants, if no software licensing costs. However DB's comments in relation to the relatively small proportion of total project cost which is represented by software are very much to the point. When you look at costs of Process Analysis, Process Redesign, Requirements Definition, Vendor Selection (Application and Implementation services), Design, Build, Test, Train, Deploy, Change management – really the cost of the software is not the big issue.
There may be times when selecting Open Source is the correct decision, for an organisation – be it the best specific business solution, the preference of an organisation, whatever. But to see this decision as the panacea in terms of significant cost savings, I would have serious reservations in many cases.