One of the things you can do to help make information about the laws of gravity more accessible and understandable to children is to conduct simple demonstrations to illustrate some of the principles. For example, you might do Galileo's experiment in which he measured the acceleration rates of balls rolling down inclines at various angles. Or you could use a spinning rope to show how NASA hopes to someday simulate gravity for astronauts with a spinning torus.
Create a bulletin board display that explains aspects or theories about gravity. For example, you can have a photo of astronaut Dave Scott dropping a heavy hammer and a feather on the moon to show how objects in a vacuum fall at the same rate, regardless of their mass. For older students learning about Einstein's more advanced conception of gravity, you could also have a diagram that shows a three-dimensional dent in a two-dimensional plane to show an analogy for the how gravity bends 3-D space.
Video presentations can be an effective way to get some ideas and information about gravity across to students. For this, you can find a documentary series that has discussed the topic. For example, the "Connections" series with James Burke and the "Cosmos" series with Carl Sagan both had episodes that dealt at least in part with how gravity works.
Have your students write a research paper on the history of theories about gravity. This can cover early ideas of the Greeks about why things fall, or the the work of Copernicus and Kepler. Although students will probably not be able to fully understand some of this material, especially when they get to Newton and Einstein, they can at least get a better idea of how the concept of gravity has evolved and is still evolving.