“GLSEN, which stands for the Gay, Lesbian & Straight Education Network, is the leading national education organization working to create safe schools for ALL students. We strive to ensure that each member of every school community is valued and respected regardless of sexual orientation, gender identity or gender expression.”
This toolkit was developed for elementary schools, to focus on anti-bullying efforts:
http://www.glsen.org/readysetrespect
For strategies, posters, and safe-space stickers:
http://www.glsen.org/participate/programs/safe-space