Start small. Work a few basic Linux servers into the organization to prove that Linux can do the job. It's best to start with running a simple service, like DNS or a virus filter. Then you can start to introduce the need for a strategy.
Remember to think about the issue from management's point of view. Don't focus on the technology, since it's not the most important aspect to them. Instead, start with the budget. Calculate how much you think they could save with a few Linux servers. Show them case studies of successful migrations. Once they are convinced of the need to take open source seriously, you can start talking about developing an overall strategy.
This was first published in November 2005