I've been meaning to write up a review of two new books brilliantly arguing for Darwinism - Richard Dawkins' 'The Greatest Show on Earth', and Jerry Coyne's 'Why Evolution is True' (which is shorter, and covers a lot of the same ground).
In the meantime, I strongly recommend this Youtube clip of Coyne.Youtube. As well as explaining 'why evolution is true' very succinctly, he ends by showing that there is a correspondence in societies between disbelief in evolution and religion, and between religious belief and social inequality and unhappiness. So if you want to fight creationism, fight for a better society.
It's not really socialist, but it's pretty good stuff.