
iGetcha.org is a suggested opensource and free software directory for the technological sustainability of nonprofits. It's also a simple, non-techie shortlist to assist organizations with a SOHO.
Google Apps for nonprofits is free for notforprofit organizations. You can look at the details on the site but basically at the moment, the Education Edition is the free for nonprofits. Also, you can qualify for a discount on Google's Premier Edition as a nonprofit and that's only necessary if you have over 3,000 users in your organization ;)