This book was recently reviewed on Slashdot. I haven't checked it out yet, but I thought it might contain useful pragmatic arguments.
"Innovation Happens Elsewhere: Open Source as Business Strategy" by Ron Goldman, Richard P. Gabriel
A version is available on-line under a creative commons license (Attribution-NonCommercial-ShareAlike 2.0): http://dreamsongs.com/IHE/IHE.html
The slashdot review gives a summary: http://books.slashdot.org/books/05/12/21/1514250.shtml?tid=187&tid=218&a...
Good luck,
Malcolm.
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