I have some trouble understanding how a force such as gravity can work over a distance - not even needing a medium, because it works just as well in a vacuum like space. Can somebody try explaining how gravitation is able to "reach out" the way it does?

I know that Einstein's way of describing gravity involves the curvature of the entire space-time continuum. I guess he has in a way solved the force over distance mystery for gravity, but what about a magnetic force?