Found via LinuxFR a very good report about OpenSource. Everything you ever wanted to know about open source without ever asking!
This is a work of great quality and I believe objectivity, this paper is a strong piece to convince management to use open source software.

Here is the table of content:
Executive summary – Key messages
• Open Source: a r/evolution in the software industry ?
1. Open Source: definition and history
2. PROs and CONs of Open Source
3. Is Open Source really changing the software industry ?
4. Open Source in the company
5. Migration path to Open Source
6. Review of cases
7. Case study, NewCo in Electricity Distribution

– Web site of the author: Salvino A. Salvaggio
– Direct link to the pdf file