A brand new, free wiki plugin is on the scene with truly convenient front-end editing capabilities. Wiki Lite has just hit the WordPress repository and it allows you to transform your site into a fully functional wiki. This plugin gives you all of the functionality you would expect from any major wiki platform but without all the hassle of having to install wiki software alongside your blog.
Users with the ability to edit posts can create and edit wikis on your site. The wiki pages can be added from the front-end or via the WordPress dashboard: