CYBER SCOUT; Reds and Yellows On the Screen and on the Trees By BOB TEDESCHI Behind football and baseball, leaf watching is perhaps the most popular fall spectator sport, but it involves jostling for prime viewing position. And with each passing autumn, those with Internet connections have an increasing edge over their unwired counterparts in finding the best leaf-gazing spots at the best times. Kaia Monroe, a Brooklyn resident who divides her time between ”freelance