Overview: A wiki is a collection of collaboratively authored web documents. Basically, a wiki page is a web site everyone in your class can create together, right in the browser, without needing to know HTML. A wiki starts with one front page. Each author can add other pages to the wiki by simply creating a link to a page that doesn’t exist yet.
Wiki Module -This page provides an overview of the functionality of Wikis in Moodle.
Wiki Settings -This page provides detailed information about each of the Settings options for the Wikis.
Using Wikis -This section outlines how to use wikis after the teacher has added a wiki acivity, including some ideas for using wikis in courses as part of the learning process.
Using a Wiki for a Group Project - This article suggests project ideas for using wikis in online courses, along with some guidelines for basic setup.