ivanatahan, "Evolution and the Big Bang theory are really two separate subjects."
Not quite. Evolution is a process that is not limited to life but includes the whole history of the Universe, animate or inanimate. Life is simply a molecule that had the ability to reproduce itself. Before it acquired such abilities it had undergone intensive transformations (evolution) from Hydrogen/Helium after the Big Bang to stars to higher elements made within the stars to molecules in the planets that surrounded those stars to ever more complex assemblies of molecules that led up to the first self reproducing molecule.
As far as what happened 'before' it is beginning to be the consensus amongst astrophysicists that there is a universe of universes known as the Multiverse. Many of those universes including ours may have the ability to spawn other universes.