Generally speaking, Honor Guards have been established to honor the service, and the members who have given their lives in service to their country or profession and their families. Their purpose is to see that the highest honor is paid to their fallen brothers and sisters as well as their individual families and their families.

Following the surrender of Germany, the 82nd Airborne was ordered to Berlin for occupation duty. In Berlin General George Patton was so impressed with the 82nd's honor guard he said, "In all my years in the Army and all the honor guards I have ever seen, the 82nd's honor guard is undoubtedly the best." Hence the "All-Americans" became known as "America's Guard of Honor."

source: http://www.bragg.army.mil/www-82DV/History.htm

Also the Society of the Honor Guard Tomb of the Unknown Soldier has a website: http://www.tombguard.org/

You can learn about the US Air Force Honor Guard here: http://www.bolling.af.mil/orgs/OG/HG/Index_HG.htm

There is also a website for Honor Guards with an extensive listing of Military, Veteran, Law Enforcement and Academy Honor Guard units here: http://members.aol.com/veterans/warlib6q.htm

Thanks tomtom22 and Missileer for your help.