We have used the Problem Frames approach to teach software requirements analysis in an undergraduate software engineering setting for several years. Its lightweight formalism is rigorous without being intimidating, and its clarity and precision foster critical inquiry and careful reasoning among students. To guide newcomers to Problem Frames, and to aid experienced students in tackling larger problems, we have created a Java-based editor tool called PFEdit to construct and manipulate Problem Frame documents. This course module includes introductory presentation material, a documented version of PFEdit, and an annotated Problem Frame document that demonstrates the major concepts of Problem Frames and the capabilities of PFEdit.