The major national resources for Gay-Straight Alliances are GSA Network and GLSEN.  Each has fabulous information for starting and running a GSA and has a wealth of ideas for activities and events.  They also love questions, so don't be shy about contacting them!

GSA Network
You can order videos and posters, find information on your legal rights, and download important research and reports that can help you advocate for change in your school.

GLESN:  About Gay-Straight Alliances
Gay-Straight Alliances (GSAs) are student clubs that work to improve school climate for all students, regardless of sexual orientation or gender identity/expression. 4,000 GSAs are registered with GLSEN.

Jump-Start Guide:  GLSEN has created a series of 8 how-to guides for new and already established GSAs. The resources take you through the process of establishing your GSA, identifying your mission and goals, and assessing your school's climate. Learn how to make your school a safer place for all its students.