Simulation-based learning (SBL) is a recent yet promising pedagogical approach. There is a plethora of medical and business simulations. However, there is a lack of simulation tools for other areas of study, like teacher education. Furthermore, since the content of many educational simulations is "hard-coded" into the tool, educators typically cannot modify or create the simulation content. This article describes SimTeacher.com, an online simulation for teacher education (http://www.simteacher.com). The instructional design goals of SimTeacher.com were twofold: (1) to build a SBL tool for teacher education; and (2) to let educators create its content. Preservice teachers become "SimTeachers" in a virtual school, applying concepts they are learning in their college courses to teaching scenarios in a simulated environment. The virtual schools contain fictional yet interactive characters that add life to the scenarios and personalize the SBL experience for learners. SimTeachers may perform routine activities, like creating lessons plans, taking attendance or completing an Individualized Educational Plan (IEP). (Contains 1 table and 5 figures.)