As school reform efforts demand that schools become places of excellence for all students, educators committed to these reforms face enormous challenges, not the least of which is the education of teachers. Although the responsibility for improved schooling must be shared among administrators, teachers, parents, and students, school reform efforts place a tremendous weight on teachers, especially those who have received no preparation for teaching English language learners. Clearly, professional development plays a role in equipping schools to meet the challenges facing these teachers. This digest focuses on professional development for teachers in culturally diverse schools. It summarizes what is known about effective professional development and the conditions that allow it to succeed. It provides three examples of professional development that are grounded in the academic achievement of English language learners as a fundamental ingredient to overall school success. (Contains 21 references.) (VWL)