In a structural phase transition, we observe a change in the symmetry of the arrangement of atoms in the solid. Group theory is a powerful tool for understanding these changes in symmetry and also for organizing the information about how the arrangement of atoms changes during the transition. Over the years, we have developed tools which allow users to apply group theoretical methods to phase transition problems without having to understand the details of the theory itself. Recently, we have developed a web-based application which allows the user to explore possible phase transitions and visualize the resulting changes in atomic arrangement. I will demonstrate a number of applications of this tool.