I have a Canon 350D, and while it is an excellent camera it only shoot's at 3 fps (frames per second). During the summer I like to photograph small equestrian events, the problem is that once those horses get moving I find the camera does strugle a bit bit to keep up with the faster action sometimes, causing me to miss shots.
I feel that for sport's photography you should be looking for a camera that shoot's at 5 fps, and if you do decide to go with Canon that currently means the 30D.
One point worth making is that the 30D is heavily rumoured to be repaced by Canon very soon (Feb/Mar) with a newer model, the 40D (or called something simular).
If this happens then you'll probably find that the price of a 30D might fall a bit further making it an excellent buy.
