The 1940 U.S. Census will be available from the National Archives website on Monday, April 2 at 6:00 a.m. California time. It will not be searchable by names, however you can search for yourself or relatives by using an Enumeration District number. Volunteers are indexing names but that won't be available for some months, possibly twelve. If you would like to volunteer to assist with indexing follow this link.
Find out how to find yourself or a family member who was a U.S. resident by reading Steve Morse's handouts "Getting Ready for the 1940 Census: Searching Without a Name Index" posted on the Santa Clara Historical & Genealogical Society's website. You can also learn how to prepare on the National Archives page entitled Start Your 1940 Census Research.
Learn more about the information you will learn about 1940 U.S. residents on the Ancestry Wiki.
posted by mb