WikiHealth (http://www.wikihealth.com/Main_Page is a collaborative writing project aiming to build a free repository on a variety of health and wellness topics. WikiHealth believes that "the more people share, the healthier they are." It's goal is to help people everywhere find optimal health.
WikiHealth differs from WikiPedia 's health content in that it also covers subjective and prescriptive content. As with any wiki, WikiHealth believes that sharing knowledge is power.