Educational organizations are excellent resources for your educational outreach initiatives. They have communication vehicles, such as magazines, newsletters, Web sites, listservs, and conferences; they have information about best practices, current research, and national curriculum standards; and they can provide credibility to your project by being formal partners. It's best if they are brought into the production early in the process when the educational material is being conceptualized. The earlier you bring educational organizations in, the more likely it is that they will feel true ownership for the project and invest their own resources in making your project a success.
You can find an educational organization supporting any curriculum area or age group, including the National Science Teachers Association, National Council of Teachers of English, International Reading Association, National Council for the Social Studies, and National Middle School Association.
The National Staff Development Council (NSDC) provides information and standards for teacher professional development, and the International Society for Technology in Education (ISTE) can help with resources and standards for educational technology professionals.
Education Week, the weekly education newspaper, has put together a useful listing of all the major organizations involved in education with links to their home pages.