It's one thing to learn about the enormous mess our environment may be in, and yet another to know what to do about it. The frustration we as adults feel can be even worse for children who often feel powerless to impact their world. In fact, children have a vital role to play, and "Kids Can Save The Earth" is an electronic primer for their efforts. Here are 6-megabytes worth of ecological materials -- information, illustrations, definitions and proposed solutions -- gathered from school children celebrating Earth Day 1990.