I would like to start an open source project, and would like to do a collaborative effort in starting it.
I have a clear idea of what I want, but not yet a formal specification (I would like to do also the design as a collaborative effort, as well as the choice of the language and platform).
What should I do before the start?
Then where should I host the project and especially where can I advertise it to find collaborators?
Is there a (free) tool to help the collaborative design? Can I simply rely on a wiki + forum?
I wrote the question as generic as possible in order for being useful for all the audiences.
I know that usually open source projects just starts with the initial work of one or few developers, but I'm really trying to avoid that development model (I want to start from scratch in a collaborative way).
Please don't answer "you shouldn't" (which would be an off topic answer). I want to go that way anyway, starting by building a "product team" just like any company would do for any non-trivial project.