I have a short list of some other sites. For U.S. government and military employees, start at the Yahoo page. Some military base sites have locator search engines that will give you the work address and phone for the employees on the base, military and civilian. If you cannot find a locator, but can do a search, search for the person's name. You may find them listed on a document they have published or on a list of orders approving officials.
Similar sites exist for county, state and local governments.
Here is a sort cut to the Air Force . If you can't find your subject's name on the web but know he or she is in a military service, go to the service's locater site, for example the Air Force and follow the instructions. They will even forward a letter to a retired member for you and the member can decide if he wants to answer. Your subject might belong to a professional association for his occupation. Accept the Disclaimer then, finely, you get to the search screen where you can search by name or specialty.