Wikipedia
GuideStar USA, Inc. is an information service specializing in reporting on U.S. nonprofit companies. In 2010, their database contained over 5 million IRS Forms 990 on 1.9 million organizations.
GuideStar was the first central source of information on U.S. nonprofits. According to the company, GuideStar was founded in Williamsburg, Virginia, in September 1994 and received tax-exempt status in 1996, the same year the company began posting nonprofit organizations' financial reports to the World Wide Web.
GuideStar's operations include data digitization, database management and development, nonprofit services, web site operations and research. GuideStar also serves to verify that a recipient organization is established and that donated funds go where the donor intended for individuals looking to give in the wake of disasters or during the holiday season. Those interested in reviewing a nonprofit's recent Forms 990 can register at GuideStar.org and download them for free, however most other information is available for a fee.