I'm watching the funeral procession on Fox News and they keep focusing on a riderless horse with a backward boot in the stirrup. Can anyone clue me in on the significance?

It is a symbol of a fallen leader that will never ride again. It dates back to the Civil War era (I think). Both boots on a riderless horese are turned backwards with a sword on the right side.
Another note - the caisson he was carried in was built in 1918? and was first used with President Lincoln.

It is truly a touching memorial for one of the greats of our time. I still remember when he said:
"Mr. Gorbachev ... tear down that wall"
And they did.

The current caisson was constructed as an Army Ceremonial Caisson (the wagon behind the cannon that carries the shot and powder). It would be tough to have Lincoln on it as he died in 1865.

The catafalque, however, is the same one that was built for Lincoln. The catafalque is the pine stand that the casket rests on while the the deceased lies in state. It's been used for a variety of individuals. The list is rather long.

Hehe - that would make it tuff, wouldn't it.
You're right.