Linux Adoption in the Workplace
One author, Mimi Yeh, states her (his?) opinion here:
However, I have a sneakier approach. The trick is to get users used to using OpenOffice.org on Windows instead of MS Office, first. Then, harp on the fact that this is free. Once they get used to it, you'll start to hear people brag about how OpenOffice.org is so user-friendly, while others may still dislike it. You then try to work with those folks to share your knowledge on overcoming obstacles.
Then, you start to look for Linux equivalents to all the apps the business uses and you ramp that up and test it to see if you think users would be willing to make the switch.
Once this is achieved, it's easier to switch users to a slightly locked-down version of Ubuntu if you customize it to look as much as possible to look exactly like Windows. (In fact, I once made GNOME look almost 100% identical to Windows XP's default desktop, although when you clicked the menus it started to look a little different.)
But to pull that off, it has to come from the top down on the benefits of cost and security from viruses, spyware, exploits, spam, etc.
Your best bet is small to mid-sized businesses -- forget about the Fortune 1000 for now. When the small and mid-sized businesses start to tilt the meter, the Fortune 1000 can be attacked a lot easier.
However, have I pulled this off? No, but I did switch a small company to OpenOffice.org on Windows and they love it much better than MS Office. They also like the fact that it's free, of course. The business is a carpet business and unfortunately they are in love with a DOS-based app specifically designed for carpet stores that interacts with a Windows-based database backend. They do, however, hate spyware, viruses, and so on, and I've not been able to keep their Windows rock solid.