Once the census pages are online you can access the first page of the enumeration district and look through the pages for the people you are looking for. You can also watch the Legacy webinar “Navigating the 1940 U.S. census” presented by Thomas MacEntee. It is available to view for free until March 19, 2012.
About that index. There are opportunities for volunteers to help with indexing the census through local genealogy organizations or Family Search. The more volunteers, the quicker we have an index. It’s not difficult and is good experience. Get more information or sign up at https://www.familysearch.org/1940census.