Open Source Tools For Documentation Creation?

chuqui asks: "I'm looking for some help from the /. group mind. I have a consulting opportunity that involves a large, complex system. Designing and building this beast is going to require a wad O'documentation, and I'm looking for ideas and tools to help deal with this, especially with flow diagrams and flow charts (I could adapt a traditional flowcharting tool, but these are more process diagrams than code flowcharts), and some way of documenting a good sized SQL system, with the schema, the tables and the connections..." If there is a single tool that can do all this, I would be pleasantly surprised, but I'm sure that there is a decent suite of tools that can be collected from the Open Source Software Catalog that would be perfect for this type of work. Right?

"I've found some tools I could use, but they all live on That Other System. The place I'm doing this for is open to considering Open Source tools for the project, so I have a chance to throw a couple of more chinks into the IS ivory tower armor if I can find find the right tools.

So I'd love some feedback from the group mind: what tools do you use to help keep a handle on large project designs, especially those involving database systems. I need process flow documentation and a way to manage the database definitions, but I'd love to hear about all of your favorite tools. I'd love to be able to bring forward a complete project management solution that's open source, just to prove it can be done to the people who believe life begins and ends with three letters and white coats...."