Here's some video I spliced together from the March yesterday which will give you an idea of the youth element and energy of the event.
Also, at about 3:25 in there's a shot from the West Lawn of the Capitol looking back which gives a good idea of the size of the crowd. In many of the news photos I've seen the crowd in front of the Capitol doesn't look that large, but what they don't show is the huge mass of people stretching down Pennsylvania Avenue that couldn't even get on to the lawn.
Also, this video includes a brief interview with Cleve Jones.
Watch, AFTER THE JUMP…