Among the many free websites offering a growing number of names of veterans who served in the U.S. armed forces is:
http://gravelocator.cem.va.gov/
One of the first such online databases is from the National Park Service featuring brief data on veterans from the U.S. Civil War. If you find a name with initials and want to know more, try googling that name with keywords +Civil War and/or +Confederate or +Union. There are TONS of databases available of various Civil War units.
http://www.nps.gov/civilwar/soldiers-and-sailors-database.htm
My dad served in the Army and was stationed in Korea during that war--I mean, "conflict." Until recently, there were not many websites devoted to those veterans. Some that I just discovered are:
http://www.butlercenter.org/koreanwarproject/ This admirable site is for Arkansas Korea War veterans.
and West Virginia's: http://www.wvculture.org/history/wvmemory/wvvetmem.html
The National Archive (NARA) has several Korean War links:
http://www.archives.gov/research/military/vietnam-war/casualty-lists/index.html
And Pennsylvania has a Soldiers and Sailors Museum in Pittsburgh? I wonder how many states have similar museums.
http://soldiersandsailorshall.org/
Fold3 offers the best in military research, should you want to subscribe/pay. Many large libraries make it available to their subscribers. https://fold3.com/ Fold3 has many other databases, too. And until recently it was the best go-to place for the Native American Dawes Applications, files ("packets"), and to see actual Dawes rejection documents. Many of those same are now on Ancestry dot com, which I believe also owns Fold3. I've spent untold number of hours reading those fascinating docs, as this white chick loves her Indian Territory history.
Nice seeing you here. Thanks for reading!