Helping Students Avoid Plagiarism - Tips and resources for teachers from the University of Maryland University College's Effective Writing Program.
Strategies to Promote Academic Integrity - USCB's Associate Dean of Students provides several guidelines on detection and prevention of cheating, many of which are applicable to web resources.
Thinking About Plagiarism - Teaching students how to handle sources, along with regular discussions (not harangues) in courses about plagiarism, cheating, and academic honesty are better pedagogic alternatives to constant policing. Provides annotated links to many resources for assignment design and understanding plagiarism.