WeBWorK is an open source, web-based homework delivery system designed to make homework more effective and efficient for students of mathematics and the sciences. It has been used for over 15 years by hundreds of professors and in a wide variety of instructional environments. Participants in this PREP workshop will develop the technical skills necessary to identify, edit and create high-quality WeBWorK problems. These skills will be cultivated through a series of four interactive web conferences and concurrent on-line group work. Participants will be challenged to formulate problems so that they not only validate skills but also foster learning. Design tips for enhancing problem presentation will be proposed. An additional preparatory web conference will be scheduled to provide an overview of the WeBWorK interface for participants with no prior experience. Participants will become active in the greater WeBWorK community and make their own contributions to the WeBWork Open Problem Library.