501(c)(3) Non-Profit Status
IRS
http://www.irs.gov/pub/irs-pdf/p557.pdf (Washington, D.C.: U.S. Government Printing Office). This IRS paper outlines the rules we have to follow as non-profit in order to maintain that status. Esp. important are the various reporting regulations (chapter 2, page 8ff) and donor interaction obligations (page 13ff).
Resources
http://foundationcenter.org/ - Foundation Center Information about how to start and run a foundation.