Case Study Resources:
National Center for Case Study Teaching in Science (NCCSTS) provides case studies for you to use in your classroom. There is annual fee of $25 to access the instructor resources if you need them. They have an extensive case collection which can be found here: http://sciencecases.lib.buffalo.edu/cs/
Science Case-Net : A network of educators using science cases.
Problem -based Learning in Biology with 20 cases and a brief description of how to use cases in the classroom.