I don’t know how I missed it but FamilySearch has completed posting their index to the 1940 US census. I like their index better than the one on Ancestry.com. It appears to be correct more often.
Currently on the FamilySearch homepage, is a link on the upper right corner which says that “all 50 states now searchable.” That it wrong on 2 minor points. First, that there were only 48 states in 1940. Also besides the territories of Alaska and Hawaii the index does include Guam, Canal Zone, US Virgin Islands and the District of Columbia. When you go to the search page, at the bottom of the page is states that you can select to search. Missing is Guam, Canal Zone and the Virgin Islands. In order to search just those territories, you can click in the “State” box up on the top of the page and it will open a selector to pick either a territory or state.
Now that the 1940 census has been indexed, FamilySearch has moved on to indexing US Immigration and Naturalization records.