Incubators are organizations that aim to decrease the learning curve for new schools and increase the likelihood that promising school plans will succeed. Incubators offer communities an innovative new way to support locally-initiated school designs. This design guide is intended to help people who are interested in starting a school incubator understand the key decisions they will have to make and learn from others' experiences. The information in this document represents a distillation of several sources of information including a meeting of school incubator operators in 2002; a review of school incubator internal and external evaluations; a literature review on business incubators; and interviews with heads of business incubators in Washington State. Appended are: list of and contact information for existing school incubator programs; and a comparison of different approaches to increasing the supply of new schools; and a planning sheet for designing program offerings.