Mark,
I would start with the Veterans Administration's Nationwide Gravesite Locator, at
http://www.cem.va.gov/ This lists everyone (as far as I know) who is interred in a National Cemetary, ie, one run by the VA. Since any veteran can request burial in a National Cemetary, this will have many who died after the war.
If you can't find them there, post the names and I will see what I can find on ancestry.com (I do have a membership).
Frank.