Theisitic evolution is a branch of Christian theology that states that evolution was a tool used by God to create what is seen today. It is strongly endorsed by the Catholic Church and many sects of many Christian denominations.
The endorsement by the Catholic Church does not come as a surprise to many. After the truth behind Galileo Galilei's theories were proven beyond all doubt, the Church found itself in a sea of embarrasment (as a side note, the Church retracted its excommunication of Galileo in 1993.) Nowadays, it refuses to find itself swimming in such embarrasments, and has actually created many research institutions so that it can say it is at the forefront of science.
It is not, as many Bible literalist Christians would have people believe, a compromise on faith, religion, or doctrine. It very strongly re-affirms the presence of God in everything around us. In fact, it may require a far greater presence of God than is allowed in Creationism, since God would have to guide the reproductive process of all organisms.
Many Creationists also mistakingly assign sinfulness to death, which is, admittedly, partially necessary for evolution, but has no moral standing in and of itself. That would mean that all carnivores are immoral, and Christians should therefore be vegetarian, but it is interesting to note that few Bible literalists are vegetarian.
The Creation story for endorsors of theistic evolution is nothing more than a spiritual insight into humanity and nature. The spiritual truths proposed by the Creation story are not in any manner undermined by the theory of evolution. Evolution proposes no spiritual truth, and so the argument of fundamentalist Christians that evolution is purposeless and unguided is considered to be of unfounded logic and reasoning. Evolution states nothing more than how living organisms came to be the way they are.
Endorsors of this theological idea often find themselves in disgust when reading up on the pseudoscience often proposed by Creationists and see it as nothing more than bearing false witness. Rather, they understand the minuteness in chance of there being life anywhere in the universe, much less the evolution of humans. They propose that God pushed chance in the direction of the creation of life and of human beings. They believe that, by itself, chance could not have created life on any planet within the universe, much less human beings should life have ever been created.