A few weekends ago I gave a talk at Ohio LinuxFest: Yes, You Can Run Your Business On PostgreSQL. Next Question? (slides freshly posted.) The talk isn't as technically oriented as the ones I'll usually give, but rather more inspirational and encouraging. It seemed like a good and reasonable topic, centered around Postgres but applicable to open source in general, and it's something I'd been wanting to get out there for a while.
In a previous life I worked with Microsoft shops a bit more often. You know, companies that use Windows and related software pretty much exclusively. This talk was, more or less, a result of a number of conversations with those companies about open source software and why it's a valid option. I heard a number of arguments against, some reasonable, some pretty far out there, so it felt like it'd be a good thing to gather up all of those that I'd heard over time.
These days I don't interact with those companies so much, so I was a little worried at first that the landscape had changed enough that the talk wouldn't really be useful any more. But after talking with a few people around the conference a day or two before the talk, there's definitely some companies that don't see the value in open source technologies.
The slides are essentially a rough outline, but I tried to go back and add some of the spoken context. Anyway, enjoy, and hopefully it'll help you get the open source word out.