I think the Irish school curriculum deals appropriately with creationism, i.e. it doesn't mention it at all to the best of my knowledge. They have enough to teach as it is, and I expect American schools are in a similar situation.
One of my university courses dealt with the history of geological research, and creationism got a mention right at the start as 'this was what geologists thought over a hundred years ago, and have since rejected as more evidence was discovered'. Honestly, I didn't know there were any modern creationists until I stumbled into EvCForum. I really thought people had tossed it out along with thinking the earth was flat and disease could be cured by bloodletting.
Should creationism be taught in schools? No. It's not science, and can't be taught in science classes. It pretends not to be religion, so can't be taught in religion classes. 90% of it is uninformed and unsubstantiated claims, random attacks on actual science, quote-mining and misrepresentation, scare-mongering, and outright preaching; and there is nothing like a consensus on what particular view of creation science is the 'right' one.
In short: it's too schizophrenic, for want of a better word. Too bizarre and contradictory and at odds with itself. Trying to teach it would probably give many good teachers severe headaches and waste too much of their time.
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