There's a fairly interesting article on NewsFactor about making the pitch for Linux and other Free/Open Source Software to corporations. Because FOSS enthusiasts understand and recognize the value of open source code, they tend to base their sales pitches on that as well. However, in an environment (aka Microsoft customers) where source cose access is a completely alien concept, this will only turn off and/or confuse the managers.
It goes on to state that in recent years, as more corporate entities themselves get involves in Linux (Red Hat, SuSE, etc.), pushing source code access has taken a back seat to simply pushing it's reliability and performance.
Pretty good read, overall. Here's the full story