The good news is that the 1940 United States Census will be released by the National Archives on April 2, 2012. Their webpage gives a preview now, with comparisons, interesting facts, and nostalgic posters and photos at http://www.census.gov/1940census/
The release of records regarding individuals is delayed for 70 years after census completion to preserve privacy of information. There has been talk about delaying even further, since more and more people are living long enough to see themselves in a census or three. But this year we get a glimpse of life in 1940 on a street by street, name by name basis.
Then there's the bad news. The information released on April 2 is raw data, so indexing is needed. You can join in the project. go to https://the1940census.com/ to sign up!