Swampy, starting out you probably want to use AV mode. If it's strong sun, ISO100 should be fine, if it's cloudy ISO200 to 400. Your aperture will vary depending on the type of shot you want and the quality of your optics. To freeze motion and create some depth of field, use a wide aperture like F/4 or F/3.5 if you can go that wide. To create a pan, where the background is blurred and the bike is sharp, use an aperture of F/8.0 - F/11. Be sure that gives you a shutter speed of at least 1/125 or higher, otherwise your shots will be too blurry. And realize that panning - turning the camera to follow the bike/car - takes a lot of practice to make perfect.

Most of all, have FUN and experiment with different settings to see their different effects on the photos.