Nonprofit organizations with 501(c)(3) status are required to file Form 990, Return of Organizations Exempt from Income Tax, with the IRS. The form includes financial statements and background information on the nonprofit, including salaries of key employees (i.e. director, head, officers). Not as detailed as 10K reports.
Access to these reports must be provided during regular business hours. All 990 Form information is available from the nonprofit or the IRS. Most are available on the Web through the sites below.