A WikiProject is a place for editors of articles of a particular subject area to work together. There they coordinate their efforts, create guidelines for the subject's articles, and much more. A WikiProject's pages are not used for writing encyclopedia articles directly, but as resources to help coordinate and organize the group's efforts at creating and improving articles.
The discussion (talk) pages attached to a project page are a convenient forum for those participating in that project to talk about what they are doing, to ask questions, and to receive advice from other people interested in the group's work.