On April 2, 2012 the National Archives will release access to the 1940 Federal Census. This census, accessible online free of charge from the National Archive at http://www.1940census.archives.gov/, does not have a name index. But no fears, if you know where someone lived in 1940, you can search the 1940 Census enumeration district (ED) maps for an address and then locate the ED number for that address.
The National Archives have uploaded the 1940 Census maps to their Archival Research Catalog (ARC) and plan to add them to the new Online Public Access system before April 2nd. To search the maps go to ARC at http://www.archives.gov/research/arc/
For more information on locating your ancestor read Rebecca’s article on the National Archive’s blog.