Grassroots.org offers a ton of great resources for nonprofits. The best way to describe them is simply providing the first paragraph from their website.
“Grassroots.org provides free capacity-building services for nonprofit organizations. All of our free services are conveniently packaged in the Grassroots.org Toolbox: a suite of free user-friendly tools designed to help nonprofits achieve, sustain, and expand a strong web presence. The Toolbox is free for all of our nonprofit members.”
Visit their web-site to sign up and take advantage of this resource.