Wikiality: "When Wikipedia becomes our most trusted reference source, reality is just what the majority agrees upon." - Stephen Colbert, satirist (2007)
There are several reasons why you should not (and usually cannot) cite Wikipedia.
For starters, according to their site "Wikipedia is not considered a credible source." http://en.wikipedia.org/wiki/Wikipedia:Academic_use
Does Wikipedia have a place in education? Yes...sort of.
We advise special caution when using Wikipedia as a source for research projects. Normal academic usage of Wikipedia and other encyclopedias is for getting the general facts of a problem and to gather keywords, references and bibliographical pointers, but not as a source in itself. Remember that Wikipedia is a wiki, which means that anyone in the world can edit an article, deleting accurate information or adding false information, which the reader may not recognize.
For a humorous take on editing Wikipedia entries, please see the Colbert Report clip on the topic.