The NBC Olympics site has put up its Equestrian highlight videos. Zara’s lovely xc ride and also a video of some of the falls, so you can get a better idea of what happened. Other Equestrian videos are posted as well.
Zara Phillips xc: http://www.nbcolympics.com/video/equestrian/highlights-zara-phillips-cross-country-individual.html
Falls: http://www.nbcolympics.com/video/equestrian/highlights-crashes-in-cross-country-eventing.html
You can also see the full Eventing jumping final here: http://www.nbcolympics.com/video/equestrian/eventing-individual-team-jumping-final.html