The 1940 US Census images will be released by the US Archives in about nine months. This is an event of great interest to genealogists. If you want to track the exact time remaining, check out the official countdown clock:
1940 Census Records
Countdown to the release of the 1940 Census,
April 2, 2012!
At the Southern California Genealogy Society Jamboree 2011 in Burbank earlier this month, Joel Weintraub gave an information packed presentation about this census and the difficulties of searching it until name indexes can be completed. Into this breach Weintraub and his colleague Steve Morse have fearlessly jumped. They have been readying a "1 Step" search engine patterned after their successes with "1 Step" search engines for immigration records and similarly complex databases of interest to family historians. Perhaps the most well known of his search engine is for Ellis Island records. A complete list of such useful tools
Currently vendors, who provide name indexes to earlier US Censuses, estimate that by this time next year, name indexes will be available for some states--most probably the smaller ones. It is probable that complete name indexes for the larger states will not be available until many months later.