Finding out military info!

My grandfather died in 2005 he was 96 y/o and he was in WWII. He would never talk about the war and I would like to find out some information on him. I know that he was awarded the Purple Heart somewhere in the Pacific. I was wondering if anyone knew of any online services that could help me find out where he was stationed and some other general info about him. Preferably free. I would also like to find out some info on my dad and my uncle. They were both in Vietnam, and they too never talked about their experiences, I would like to know more about them. They have both passed on also.
Thanks for your help. I want to know more about my family so I can pass on the fond memories to my son. He will never know the great men that were my father, grandfather and uncle. But I will let him know they were great men.
Thanks for the help,
Rich

 

The link below will take you to the National Archives and their page containing information on retrieving military service records.

http://www.archives.gov/veterans/military-service-records/get-service-records.html

Unfortunately, many records from the World War II generation were destroyed by a fire. Good luck with your hunt!

 

Do you know where in the Pacific he was or what unit he was with? I studied WWII in depth because my history teacher had family fighting for both sides. What a family reunion that must have been. But seriously the books I used went to great detail about the units and some people and recipients of awards.