As an aside, the issue with Intelligent Design is a subset of whether belief in God can be scientific. Note that the question isn't whether it can be right but strictly scientific.
For any given test of whether God exists and intervenes in the universe, there are only two possibilities. Said God may be consistent and do the same thing every time -- in this case, God's action is indistinguishable from the laws of nature. Alternatively, God may act only in specific situations, leaving natural law in force the rest of the time. This would be considered a miracle, and is inherently untestable.
Science cannot test the existence of God. Science is a very useful tool, but only when applied to its proper domain -- if it can't be tested, it can't be approached. Science can tell us, e.g. that the physical parameters of the universe and the location of Earth are *just* right for life to have arisen. What science can't actually tell us is whether that's the case because Someone made it that way, or whether with so many planets in the cosmos it had to eventually happen somewhere.
Microevolution, the development of specific traits within a species, is more or less unchallenged. There are some, including me, who question whether macroevolution adequately explains everything and whether there's sufficient evidence for it. Other Christians take the view that macroevolution could be the tool God used. There are some who stand on a boundary -- C.S. Lewis (I forget which book) presents a possible story by which Adam and Eve are partially allegory. Evolution progressed to a certain point, and God chose two of the pre-simian creatures and invested them with souls and the capacity to understand right and wrong. There are a lot of views out there....
