Is there a site with a listing of the different types of military awards and medals, explaining what they are given out for ? Also which is the highest honor ?

In The United States The Medal of Honor is the highest.

The President, in the name of Congress, has awarded more than 3,400 Medals of Honor to our nation's bravest Soldiers, Sailors, Airmen, Marines, and Coast Guardsmen since the decoration's creation in 1861.



You can learn more about ribbons and medals here.

Actually, George Washington awarded 2 medals of honor to a couple of his guys, but the awards had more similarity to the purple heart than today's Congressional Medal of Honor. The medal was reinstated in 1861.

Here is listing of the medals and why they are given. (Broken down per branch)

USA

USAF

USN

USMC

USCG

Hope this helps
Thaddeus

P.S. There will be some cross-over of medals, but each site has the branch specific ones.