I just read this essay by Bruce Schneier: How to Sell Security. This is definitely a must-read in my opinion. Not that it really tells you how to sell it but it helps you to understand the “mechanics” about it. Roger
About the author
Roger Halbheer is an Executive Security Advisor at Microsoft in EMEA acting as a trusted advisor to CxO. Before that he was a Managing Director at Accenture's Financial Services. Before joining Accenture, he was the Chief Security Officer of Swisscom (Switzerland's largest telecom provider) and the global Chief Security Advisor for Microsoft.