Then here's the scoop. Evolution is a fact. As much a fact as the existence of atoms, gravity, and germs. Where the theory part enters the picture is in explaining how evolution works, just as atomic theory explains how atoms work, and the theory of gravity attempts to explain how gravity works.
Another point worth noting is that the term "Darwinism" has become a pejorative label for evolution. While Darwin was extremely important to evolution, the theories that explain it have gone far beyond Darwin's understanding of its operation. So, to call evolution "Darwinism" is ignore all the advances made in the field of evolution and suggests evolution is stuck in the 19th century. It's a rather childish practice, but one creationists delight in using, much like many of the other facts they purposely ignore in order to make their case. The cartoon here isn't far off the mark.