Diane Murely has a a good article in Law Library Journal about the merits of Wikipedia. Her conclusion:
From Legal Research Plus.
Wikipedia can be a great research tool if used appropriately. Students and lawyers should be taught to use it as a quick reference source for nonlegal questions or as a research starting point with references to other, reputable sources. Librarians and other research instructors should demonstrate how to evaluate Wikipedia articles for authority, completeness, bias, and accuracy. Because Wikipedia provides so much information with which articles can be evaluated, it is a good tool to use to teach researchers about the necessity of evaluating sources.I couldn't agree more.
From Legal Research Plus.