This paper describes the development of a simulation in teacher education. The presentation we will demonstrate a pilot version of the software and report on our research into its use by pre-service teachers. The simulation allows users to take on the role of the teacher of a simulated Kindergarten classroom (ages 5 to 6 years). During the simulation the user makes decisions about organising the lesson, classroom management, and responses to individual students. The user can monitor and track the progress of three targeted students throughout the course of the simulation. Embedded tools serve as a "decision assistant" and a "thinking space" are used in order to plan and justify new decisions, and to reflect upon the consequences of previous decisions. Supports are added include links to: textbooks; the K-6 English syllabus (Board of Studies, 1998); support material from the New South Wales Department of Education and Training; sample artefacts collected from classrooms.