I own a Nikon D60 with a 18-55mm and a 55-200mm. I encounter the exact same problems you encounter. There are a few ways, that I know of to help fix/get around this issue.
1) Set it on manual, open the aperature as wide as possible, and see how high you can get you shutter speed before it starts to get to dark. I run around 1/250th to 1/500th depending on the time. During warmups, 1/500th on shutter priority with a ISO of 400 is pretty good. During the later parts, I run on 1/250th (or 1/200th if I'm using my flash) with a ISO of 1600 or Hi 1 (which I'm presuming is Nikon's D60 variant of 3200...could be wrong).
2) Metering. First off, go into your settings, and where it says AF/AE lock, set it to AE only. Find a dark spot (i generally use my school's track as it's black or my shadow...if there is one), point your camera at it, press the shutter button down half way, wait for the camera to meter, press and hold the AE lock button, let go of the shutter button, raise the camera, focus on your target, and start shooting. This
should result in your photo being brighter. If it's two bright, raise the shutter speed up a bit and do the process again.
3) Fast glass...ftw. Every now and then, I might bust out my dad's D300 with either his 200mm f/2 or his 400mm f/2.8. All depends on where I'm at, what type of sport, and the time. I use the 400mm for the JV games as they're earlier and so that I can sit down and save my back for the 200mm during the V game coming right after it where I'm running back and forth down the sideline.
4) Post-processing. If you're pictures come out grainy (noisy as others call it) run it through a program that basically removes the grain...I think it's called Noise Ninja, or something like that. Pictures coming out dark? Run it through photoshop or gimp or another picture editing program. Crank up the brightness, adjust the color, and fix anything else that needs fixing.
Gimme a second...I have a Kodak book that recommends shutter speeds...hold on...hmmm...let me find it.
*begins digging in his cluttered closet*
AHAH! Found it. Oh...never mind. Doesn't have football in it.
Here's an example:
During the higher light times of the game (like warm ups), I use a higher shutter speed and a lower ISO as there is enough light to deal with everything.
http://gatecrusher420.deviantart.com/art/PCHS-Football-2-136811595
^That is an example. Shutter speed of 1/500th w/ ISO 400.
Now...for low light...well...I'll have to upload one for you to show you what you'll get. Wait...I have one uploaded.
http://gatecrusher420.deviantart.com/art/PCHS-Cheerleading-7-136789328
^That's 1/200th of a second w/ ISO 1600 WITH a flash at about 40 feet...maybe less.
Another:
http://gatecrusher420.deviantart.com/art/PCHS-Cheerleading-6-136789104
^That's 1/160th of a second w/ ISO 1600 with a flash.
So as you can tell, ISO helps alot, albeit, can turn a great picture, into a grainy mess. But as I said in option 4, simple post-processing can help.
Hmm...I think I might post this on my site. Good little tutorial.
I hope that helps.
