I just got out of a lunch for the Michigan delegation, where the subject of Sarah Palin's future grandchild came up repeatedly. The gist: People were still pretty excited about Palin, but somewhat anxious about how the pregnancy would play. One group of Michigan men decided it would be a wash because while these sorts of revelations are never helpful, Democrats wouldn't be able to do anything with the story.
The most interesting theory I heard came while waiting in line: A man behind me said the McCain camp should welcome the development, since it sets up a direct contrast (and presumably favorable, in this person's opinion) with Obama, who has said he wouldn't want his daughters carrying a baby to term if they got pregnant as teenagers. We'll see...
Update: As one of our commentors noted, Obama didn't say he wouldn't want his daughter to carry a baby to term; he said he wouldn't want her to get pregnant in the first place--"punished with a baby" was the phrase he used (i.e. he was talking about birth control, not abortion).