Area Median Income: http://www.huduser.org/portal/datasets/il.html
Individual Income Limits: http://www.huduser.org/portal/datasets/il.html
Fair Market Rent: http://huduser.org/datasets/fmr.html
American Fact Finder: http://factfinder2.census.gov/faces/nav/jsf/pages/index.xhtml
The US Census Bureau's data site. Data are available for the 1990 and 2000 Censuses of Population and Housing as well as the annual American Community Survey.
Dataplace by Knowledgeplex: http://www.dataplace.org/
Provides access to data from the 1990 and 2000 Censuses (demographic, economic, housing, and social characteristics), Home Mortgage Disclosure Act (home mortgage applications and loans), Section 8 Expiring Use database (neighborhood- and property-level data on federally assisted housing at risk of loss), and Consolidated Plan special tabulations (data on housing needs by household income level). DataPlace's data library will expand in the coming months to include information on topics such as business establishments from the Census Bureau's ZIP Business Patterns database and Low-Income Housing Tax Credit developments from the U.S. Department of Housing and Urban Development. DataPlace also has a mapping tool and a chart tool as well as area profiles (quick statistical snapshots of any geographic area).
State of the Cities Data System (SOCDS): http://socds.huduser.org/
HUD User data source. Includes data from the 1970, 1980, 1990 and 2000 Census; building permit data by jurisdiction; the latest available unemployment statistics; crime data; and 1990 and 2000 Comprehensive Housing Affordability Strategy (CHAS) data.
Windows on Urban Poverty: www.urbanpoverty.net
An interactive mapping site that documents the geographic dimension of poverty in the United States.