For those used to my accounts of Tokyo life, please forgive this short digression. A little while ago there was a blog asking for proof of the existance of God, and I was engaged in some amusing exchanges - however there were a couple of posters that questioned the evidence of evolution (not an unreasonable thing to do, as long as you haven't decided on the answer before asking the question) and put forward the 'weakness' of evolutionary theory as proof (or at least evidence of) God. Sometimes things need saying, even if you are sure they will fall on deaf ears. I promise I will not fall into a pattern of troll baiting blogs, and normal service will be resumed next time; although I may explain my intense dislike of the concept and realisation of religion at a later date. This post is however NOT an attack on religion, but an attempt to take some of the irrelevent stuff out of the argument.
There is a great body of literature explaining the current scientific model of evolution far better than I would be able to. I find it incomplete, but broadly persuasive, although both in its broad sweep (what exactly the factors are that lead species to change over time) and the mechanisms (there have been some interesting studies suggesting a Lamarckian physical adaption to environmental pressures I have read about, as well as much mention of a current scientific darling Horizontal Gene Transfer). But this is science, and the ideas should be challenged, discussed and considered before they are accepted.
One thing we can be sure of is that natural selection can work - It is used in adaptive algorithms in computer science and engineering, and is mathematically provable. This does not mean that it is actually the mechanism in place in nature although all the impartial evidence I have seen seems to suggest this.
However, the really important thing is that whether you accept the evolution of species or not, whether you accept the action of Natural selection or not has no impact on the liklihood of their being some supernatural agency (God, spirit or otherwise) - the argument is a different one. If you look at the evidence and decide it is probable that evolution has occurred, you don't have to stop believing in God (in fact there are those that view the mechanism as indicating a more amazing and subtle creator who has used this mechanism to shape the creation). Also, you don't have to start believing in God. The existence of God is another (albeit interesting) argument.
One of the things that particularly amuses me is the tactics of those seeking to fit the evidence to their pre-decided answers. Straw man arguments (answering as if addressing your points but in fact answering points of their own in order to misrepresent your position), and the liberal (in the non political sense of free and uninhibited) and random sprinkling of scientific terms to add 'weight' to their arguments are illustrations of this.
One of the things that particularly saddens me is that some of the best writers of popular science in this subject are also campaigning Atheists - not because I disagree with their position (in fact I agree with much of it), but because their Non-science work puts off those with very real religious conviction from understanding the science behind the slogans. Most of all, don't take my word for it - read for yourself and make your own mind up!