Depending on the sport you are covering and the weather conditions, outdoor sports will vary considerably. For instance, if you're shooting auto racing on a bright sunny day, or your grandmothers lawn dart team on a cloudy day ;), the settings will be on opposing ends of the scale. Most times I'll use an F2.8 to F4 depth of field, in order the have a nice "soft" background (making the subject pop out of the picture), and leaving myself enough margin to crank up the speed, to freeze the action, without having to boost the ISO too high, and avoid having too much digital "noise" in an image. But keep in mind, if you're shooting a football/soccer match, and the conditions switch from daylight, to artificially lighted conditions, don't be scared to boost the ISO, instead of reducing the speed. You want the ball to be sharp! For boat racing, my settings are something like this...
Full Manual Mode, F5.6, 1/1250sec speed & 640 ISO
You may also like to try and accentuate the "Speed" effect by slowing down the camera speed, to create a panning shot. Make sure you are as perpendicular as possible to the subject. In this case, I was lucky enough to have permission to be in the water. Auto racing yields better panning pics than boat racing, as there is no "up-down" motion of the subject, and they have a more fluid motion from side to side.
Full Manual Mode, F5.6, 1/40sec speed & 50 ISO
More examples of sports photography can be seen on our website, by following this link > HERE