I agree, 800ISO is perfect, since if you use anything faster, like 1200 or 1600 your camera will maybe freeze the movement, but the photos will not be high quality, since this film is too fast, and photos turn up "foggy", though you didn't do anything wrong. I use only 800.
then, I don't know what sort of camera you have, but on my camera I can choose it to focus automatically, with a "sport button" that allows the camera to work fast, and take photos of people moving past in high speed (ie skating LOL)
and....if you have an expensive camera...use a 300mm lens or more....if you want photos up a little closer....
I have a Canon EOS 300 camera, and I've been able to get good photos on several events.
Like someone said, the trick is to not shoot when the skaters are far away, it'll never be fab anyway, wait until they are close, and don't mind taking photos when they're jumping, cause it never works out
My friend from Japan brought a really high tech digital camera to Euros...but I don't know much about digital photography, so I'm not the one to give advice there