thanks. i usually just put it directly to automatic, but for folliage shots i've been using landscape or close up. i try to remember to turn the flash off as much as possible. it's tough to find a situation where the flash on a $130 camera will add really good lighting to a photo. great for candid shots and fun shots, not for when you're trying to get all artsy fartsy... they also ruin mtb photos because someone always has something reflective on.
in manual mode, if it's a decent one, you should be able to adjust both shutter speed and f-stops. focus as well. my sony let's me do that. i definitely feel limited with the point and shoot. after it figures out what setting it wants to be at, i can adjust it 4 clicks darker or brighter, but that's it. every digital i've ever used has a delay from pressing the button to taking the picture. you just have to plan ahead and time it right. press the button about half a second before you want the shot.
as for blurry action shots, the greater the angle the riders are to you(riding toward you or away from), the better the shot will come out. moving at speed for a 'perpendicular' shot will almost always lead to a blurry shot for me with an automatic, unless it's really bright out. with a manual, you can drop the f-stops super low and use the shortest exposure possible to capture those kind of shots, if your camera can handle it. otherwise, if you really want that shot, either the rider or the background will be blurry. try focusing on the rider as they approach and following them with the camera as you take the picture.