What is a Form 990?
IRS Form 990 is the tax document that tax-exempt nonprofit organizations file each year with the IRS. The 990 allows the IRS and the public to evaluate nonprofits and how they operate.
Beginning with tax returns filed in 2009 for 2008, nonprofits must file the new Form 990 that requires more disclosure of potential conflicts of interest, compensation of board members and staff, and other details having to do with financial accountability and avoidance of fraud. (source: ask.com)