With the 1940 census images now available to the public the folks over at familysearch.org have added those images to their volunteer indexing service. They have a map now showing the progress of indexing the census data, state by state. Here is what it looks like today:
Delaware was the first state to have 100% of the indexing complete. Colorado, Kansas, and Oregon are all over 80% complete. The indexing effort is very impressive. During the first three days over 2.5 million records were indexed.