Political campaign activities of section 501(c)(3) organizations are addressed in the following IRS news releases and fact sheets:
IR-2007-190 (Nov. 19, 2007): Reminding charities and churches of the political campaign activity ban.
IR-2006-87 (June 1, 2006): Reminding charities to avoid political campaign activities during election season.
Fact Sheet 2006-17 (Feb. 2006): Explaining how the IRS interprets the federal tax law provisions on political campaign intervention by section 501(c)(3) organizations; the fact sheet provides 21 examples of possible campaign intervention and explains how the law applies in each.
IR-2006-36 (Feb. 24, 2006) : Announcing the release of a report on the IRS's examination of political campaign activity by tax-exempt organizations during the 2004 election campaign.
Fact Sheet 2004-14 (Oct. 2004): Explaining the rules regarding political campaign activities of section 501(c)(3) organizations.
IR-2004-59 (Apr. 28, 2004): Warning charities that they may not engage in political campaign activities.