Hi,
I've read the project description and I think I have good understanding on what you need. I'm a technical writer and QA engineer with significant experience in web product management and in working with distributed team.
I wish to bid for this project.
As technical writer, I have created various software requirements and specifications document, mostly web applications, including e-commerce applications and social networking apps.
I can help and document they system requirements including mockup. I have worked as lead analyst and documentation specialist for a school CMS under rewrite and had documented (target users are developers) new feature and enhancements.
I have good technical backgroud and have good understanding on web applications development. As product planning manager, I created documentations for development team, and took lead role in product feature planning including cost analysis. I think, you won't need that for your project but I mention it because I wish to be clear that my experiece was closely similar to that of project manager but I was not a project manager though I did help manage projects.
I can help you to get things done. I have edge as technical writer and QA engineer and so I can drive effectively testing and QA efforts.
I can send you sample of my previous documentation work. Perhaps we can discuss further about the project including specific deliverables but I am thinking that initially, most work shall be documentation.
Thanks.