School Policy on Wikipedia: Read for background but do not cite!
Rule No. 1: Use Wikipedia as a starting point for your research, but don't cite it unless you can exhaustively demonstrate that is is the only authoritative source on a particular issue.
Rule No. 2: Re: Rule No. 1: That doesn't mean that you should use the information from Wikipedia anyway and just not cite it. It means that you should find other research sources. Encyclopedias are only meant as starting points! For example, you could find the bibliography in the Wikipedia article and look at the sources that the author of the article used. You could also look to see if there is a list of links. Check those out as well.
Rule No. 3: If you are unsure, ask your teacher or librarian!