The Defense POW/Missing Personnel Office (DPMO) has created the first electronic listing of missing personnel from the Second World War. The records came from two historical sources: Rosters of Military Personnel Whose Remains Were Not Recovered, 1951-1954, and The World War II Rosters of the Dead (All Services). POWs and MIAs are listed as well as those buried at sea. Entries on this website were created by corroborating names and service numbers that appear in both sources.
Use of the database is simple: go to the site's web page, and then look for the first letter of the person's last name. There you will find separate listing for Army, Army Air Forces, Navy, Marine Corps, and Others. The Others listings appear to all be civilians, including Merchant Marine. Service personnel who were buried at sea are listed in a separate section of the same web site.
Again, this web site contains lists only for those persons whose bodies were not recovered and those who were buried at sea.
You can access the "Service Personnel Not Recovered Following World War II" database at http://www.dtic.mil/dpmo/WWII_MIA/INDEX.HTM.