I can only go with gymbratsmom here!! The Canon 20D should be the camera for you if you want to get really good photos!!
Other cameras will still leave you with blurred action shots.....
The photos you can see on our website that have my name on were all taken with this camera just to give you an idea.
But you need a real good zoom lens, too. And I only go with original Canon lenses there. There is a difference between Sigma and Canon.
I would go for the 70-200 2.8 L USM lens if you want to get the best possible photos.
Note, that this is not exactly cheap - but it`s worth it!!