Almost all works are proytectd by copyright law.
"Fair use" allows some copying without express permission."
"Gone with the wind and the Wizard of Oz"
You can use character in a story up to a point, such as the broadway play Wicked.
Use someone else's idea=A nice law suit

Newspapers and other main stream media outlets are now challenging the online titans of blogs for readership. Many young people have turned to blogs and such for a different take on the news and the speed of which information and travel. Blogs, however, can be biased or misleading. The death of Heath Ledger issued the question of the facts of the real story. Newspaper blogs had to sort out fact from fiction such as, how many pills were in the room, was he living in an Olsen twin's apartment in New York, and who called the police. Traditional journalists now turn to online sources to keep up with the times. This method brings new questions on ethics about copyright, libel, etc. The government has passed the "Communication Decency Act" and the Digital Copyright Act to protect users and ISPs respectivly