Those kids in the south have done it again! Wonder when our stats folks
will do the same! Oh! Woe is us!
http://beta.sedac.ciesin.columbia.edu/usgrid/The U.S. Census Grids (beta release) provide raster data sets that
include not only population and housing counts, but a wide variety of
socioeconomic characteristics. These gridded data sets transform
irregularly shaped census block and block group boundaries into a
regular surface – a raster grid – for faster and easier analysis. Data
sets are currently available for the year 2000. Data sets for 1990 will
be released in the near future.
via - geowanking