Zooming [More precisely, telephoto]
The first time you try to take a picture of a shortstop, much less a centerfielder, using a camera with a standard 3x optical zoom, you'll know it's inadequate for baseball. You need at least a 10x telephoto zoom to zoom in on the action. Otherwise your software crops will be so "pixilated" that they won't be usable. [Please ignore the "digital zoom" advertised for cameras. This just means that the camera is throwing away data outside of the center of the focus. It's useless - completely.]

Motion Blur
I love my Canon SD400 Digital Elph. I carry it in my shirt pocket most of the time. But it's useless for baseball. Trust me. It's just too slow. You'll need a camera capable of stopping action, even in relatively low light, and still giving you a decent image. To stop action you need a camera with a fast shutter speed. But increasing the shutter speed means that you have to increase the size of the aperture (the opening to the lens) in order to allow enough light to produce the image. And this is where digital SLR cameras have much greater strength than the best "point and shoot" (or EVF - Electronic ViewFinder) digitals. Some of the EVF cameras are pretty good, but for baseball photography I would only recommend a DSLR (unless you will only shoot daylight games).

Camera Shake Blur
A related issue is the blur that occurs when you don't hold the camera steady (as opposed to motion blur which occurs when the subject moves). You can minimize this by holding the camera correctly, but you won't eliminate it without a tripod. To correct for this you need a stabilization or anti-shake system. There are three types.

Electronic - This is really a band-aid used on some cheaper cameras. It merely increases the shutter speed when the processor detects camera shake. The problem is that this makes it impossible to choose a depth of field. It won't be effective, either, if you are already using a fast shutter due to low light.

Optical - This system moves the lens elements to adjust for camera shake. If you are using a digital SLR system this means that the stabilizer has to be built into each lens. Canon and Nikon use this system. When you are looking at lenses for these cameras, and "IS" (image stabilization) on Canon lenses or a "VR" (vibration reduction) on Nikon lenses indicates the lens has the shake reduction system built in. Expect to pay several hundred dollars more, per lens, for this feature.

Camera Body - Instead of moving lens optics these systems move the image sensor in the camera body to compensate for shake. The advantage is that this means that all lenses you use are stabilized and you don't have to pay extra for "IS" or "VR." Konica Minolta pioneered this system as "AS" for Anti Shake. Sony has inherited it by virtue to taking over the DSLR business from KM. The Sony Alpha 100 has this system, although they call it SSS (for Super Steady Shot). Pentax has introduced a similar system - they call it SR (for Shake Reduction) - in their current K100D and just announced (September 06) K10D. Most recently, Olympus has built it into their E-Volt 510.

Both the optical and camera body systems work well. Note that you probably won't need any anti-shake system if you use only very fast shutter speeds (such as 1/500 sec. or faster). For many action shots you will use these speeds anyway. But if you are using a long lens - above 200mm or are shooting at slower shutter speeds you'll need a tripod.