The 1940 census will be released online on April 2, 2012. To follow along with the countdown visit http://www.archives.gov/research/census/1940/.The website http://1940census.archives.gov/ has been set up to access the digitized census records starting on April 2. The digital images will be accessible free of charge.
Get a head start on the census by reviewing some of the basic information available from NARA at http://www.archives.gov/research/census/1940/general-info.html#guide. The information that the National Archives has put together includes information on each column on the census form and the code explanations used by the census takers.