Joe Carter gives a fine summary of the argument for God's existence based on the fine-tuning of the cosmos. I agree with Carter that this is one of the most powerful of teh arguments for God's existence, even if it doesn't constitute a proof, sensu strictu.
I would caution, though, that the argument does not lead to the conclusion that the architect of the universe is the God of the Bible. Nevertheless, despite this technical shortcoming, the argument goes a long way in clearing away the brush that stands in the way of people accepting that the God of the Bible exists.
If we agree that the design of the universe suggests an intelligence behind the creation we might also conclude that it's reasonable to assume that that intelligence is personal, powerful, and knowledgeable since it has created personal beings and since a great deal of power and mathematical knowledge were required to create the universe. This brings us very close to the God of Abraham, Isaac, and Jacob. What we cannot infer, however, is that the architect of the space-time cosmos is unqualifiedly good. The existence of suffering prevents us from making that move.
Thus the finely-tuned universe is a compelling reason to believe that there's a creator, but the question whether the creator is identical to the God that Christians have traditionally believed in cannot be settled by reference to the physical creation alone.
Even so, the argument is very powerful. Check out Carter's discussion of it at the link.
RLC
