I have the opportunity to go shoot the first ever Motocross National to be held at night, under the lights in Lakewood, CO. I am relatively new to photography and have been studying hard to learn the relationship between aperture, ISO, shutter speed etc and how to manipulate them to the best possible outcome. I am currently shooting a Nikon D70 with a Nikkor 55-200 f/4.5-5.6 VR lens. Now, I can forsee this nighttime race presenting quite a photographic challenge. Fast motion, relatively low light, and the long end of the zoom range. I am trying to scrounge up the funds for a 70-200 f/2.8 before next week but i'm not sure it's going to happen. Any advice? I would think an external flash would certainly be of assistance, along with the 2.8 lens if I could come up with it in time. Any suggestions would be much appreciated.