Tim wrote here recently about how the library at his home institution, the University of Cincinnati, has (mis)handled its approach to Wikipedia.
Reference librarians are making their peace with Wikipedia. Colleges say they have conducted both school-wide conferences to hammer out guidelines, like Carleton did last year, to find the teachable moment to get students to think critically about the sources of all their information, online and offline.
The Carleton guidelines point out both advantages and disadvantages to using Wikipedia. Meanwhile, over at Concurring Opinions, there is some good discussion about stability and citability in Wikipedia, especially in the comments section.