I just came across an excellent article that examines if Wikipedia should be trusted and how it should be used. Truce Be Told from the Harvard Graduate School of Education looks at the pros and cons, and how Wikipedia has evolved over the years. Read the article and consider how it applies to all sources of information (including this Blog!)
Now more than ever, as students use the Internet as a resource for school projects, the idea that teachers should embrace is that proper research is accomplished the same way as it always has been. The problem isn't any particular site; one should always use multiple sources, examine their reliability, and give citation to information gained. As far as Wikipedia, ...
"Educators can use the site to teach about online credibility, fact checking, primary and secondary sources, crowd sourcing … rather than simply banning it.”