Wasn't that what the Monkey Scopes trial was all about, though? The one where Clarence Darrow made his name?
Yes. But Scopes was convicted for teaching evolution, it had to be overturned in court, and even then it wasn't until the 60's-70's that it became common to teach evolution in schools. In the 1980's Louisiana passed a law requiring Creationism to be taught in schools, which went to the Supreme Court and was overturned due to a clause in the America Constitution forbidding the Establishment of a state religion, (making it illegal from then on). Don't know how it is in Australia, but Creationism has lost pretty much all these fights since the Scope's Trial on pretty similar grounds (so from the 1920's onward). Since then, the Creationists have turned toward Intelligent Design, essentially trying to pass creationism off as a scientific alternative to evolution, so it pops up every now and then under that guise.
I'm not sure if it's 100% illegal to teach creationism in science classes (only illegal to require it be taught), for example, in my school they taught creationism in a history class as part of a world religions unit, alongside teachings from Buddhism, Hinduism, etc. but not as science. Every time it pops up, either as stickers on text books or some state legislature passing laws requiring creationism/ID to be taught with equal regard compared to evolution, the people who implemented the law tend to lose the next election and then the law is repealed.