Evolution, a Little Bit

I'm having difficulty understanding what Christians believe concerning evolution.

When President Bush says that a recently evolved avian flu virus could mutate and become transmissible between humans, is he endorsing evolution? It sounds like he is, so I'm guessing that he believes in evolution for some things. Either that or he believes that a benevolent God sees the utility of placing a specific avian flu virus on the earth that's capable of being transmitted between humans, with fatal outcomes.

If he endorses evolution sometimes, when are those times?

There's a news story making headlines recently:

University of Chicago Researchers Find Human Brain Still Evolving

Do Christians deny this? I'm guessing they do, but I don't know.

One more point, if Christians endorse evolution at all, why do they support teaching intelligent design as an alternative to it, and not in addition to it?

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Shown is an image of the April 28, 2005 edition of the journal Nature. Its cover reads:

"This journal contains material on evolution. Evolution by natural selection is a theory, not a fact. This material should be approached with an open mind, studied carefully and critically considered.
- Approved by the University Board of Regents, 2006"