Interdisciplinary database with trade journals, newspapers, scholarly journals and dissertations. Good source for nonprofit literature and research on philanthropic trends. Try searching: (volunteers and motivation and nonprofit)
Contains survey questions on donating and volunteer habits.
Foundation Directory provides descriptions of grant makers, including private grant-making foundations, community foundations, operating foundations, and corporate grant makers.
Provides reporting on U.S. nonprofit companies. In 2010, their database contained over 5 million IRS Forms 990 on 1.9 million organizations.
In general tax-exempt organizations are required to file annual returns with the 990s though there are some exceptions. The 990 is a good way to get financial information on a company and the salaries of management. If an organization that is required to file does not they can lose their tax-exempt status.
Charitable organizations are generally considered 501(c)(3) organizations. In order to be considered tax-exempt under the IRS code charitable organizations must be organized and operated exclusively for its mission and cannot spread any of its profit to shareholders or private investors.