In just a month, the National Archives of the United States (NARA) will make history when it releases the 1940 census on April 2, 2012. This census will be the first to be released to the public in digitized form. Family historians will be able to access the images from the computers at the NARA branch facilities or on their own personal computers.
However, the search will not be as easy as plugging a surname into a search engine, since the census will not be indexed by name (indexing projects are underway by the LDS Family Search and Ancestry.com). In order to find your family in the images, you will need to know their address in 1940, which will help you obtain their census enumeration district.
NARA has prepared excellent tutorials on preparing to search the 1940 census. Click on the links provided below. And don't forget to store food and water for April 2nd--you might not be able to tear yourself away from your computer!
NARA 1940 CENSUS: HOW TO PREPARE
NARA VIDEO 1940 CENSUS