[Jim Bryant]

1) Shoot with ISO 400
2) Use a high shutter speed of at least 500th second or above
3) IF you are using the Rebel on sports mode, take it off and use a higher shutter speed to stop the action.
The Rebels are a great beginner camera, but in order to capture the type of sports you want to be able too, you need to get the EOS 1D's or MKII, or MKIII series camera bodies that shoot 6 to eight frames a second.

After viewing your picture, your focus is not sharp on the players, the background is sharp, but the players are out of focus. I'm not sure what type of Al Servo AF settings your camera has, but it needs to be set so that it will follow focus with the action. I know the EOS 1D's, MKII's and MKIII's have two AF modes: One-shot AF and Al Servo AF.
The one-Shot AF is prefect for non moving subjects, where as the Al Servo AF is for moving subjects and sports action photography.