Please do not assume that all Christians are Creationists. Most Christians accept Evolution.
Most Christians do not take the stories of creation in the Bible literally. Catholics believe the book of Genesis tells religious truth and not necessarily historical or scientific fact.
Some of the religious truths are that God:
+ Created everything
+ Created humanity is His (or Her) likeness and image
+ Declared all of Creation was good
Catholics can believe in the theories of the big bang or evolution or both or neither.
On August 12, 1950 Pope Pius XII said in his encyclical Humani generis:
The Teaching Authority of the Church does not forbid that, in conformity with the present state of human sciences and sacred theology, research and discussions, on the part of men experienced in both fields, take place with regard to the doctrine of evolution, in as far as it inquires into the origin of the human body as coming from pre-existent and living matter - for the Catholic faith obliges us to hold that souls are immediately created by God.
Here is the complete encyclical: http://www.vatican.va/holy_father/pius_xii/encyclicals/documents/hf_p-xii_enc_12081950_humani-generis_en.html
And here is the Address of Pope John Paul II to the Pontifical Academy of Sciences on October 22, 1996 speaking of the Theory of Evolution: http://www.newadvent.org/library/docs_jp02tc.htm
Here is an interesting article about Pope John Paul II's opinion in the matter: http://www.americamagazine.org/content/article.cfm?article_id=4627
The Church supports science in the discovery of God's creation. At this time, the theories of the big bang and evolution are the most logical scientific explanations. However tomorrow someone may come up with better ideas.
As long as we believe that God started the whole thing, both the Bible and responsible modern science can live in harmony.
The Clergy Letter Project an open letter endorsing the Theory of Evolution signed by over 10,000 clergy from many different Christian denominations: http://www.butler.edu/clergyproject/
By the way, Georges Lemaître (1894–1966), a Belgian Catholic priest and professor of physics and astronomy, proposed what became known as the Big Bang theory of the origin of the Universe. http://en.wikipedia.org/wiki/Georges_Lema%C3%AEtre
With love in Christ.