Background
I'm in charge of auditing a medium-scale web application. I have audited web applications several times before, but I've always wrote a short PDF quickly explaining what I encountered and usually I'm the one who's gonna be fixing those vulnerabilities so I never cared for the actual contents of the report.
In my current job things are done in a way more organized fashion. First I have to write the report, then the project manager will review it, then he'll decide whether I'll be the one to fix the issues or someone else.
Question
What should such report contain? I'm looking for a general outline of how it should be organized.
Update: Because I couldn't find anything here on Security.SE about audit reports, I decided to make this question a bit broader and include any kind of security audit rather than just web applications. I think it'll be useful to more people in this case.

