Short answers, pulled from the story.
Isaac Asimov stated the Three Laws of Robotics on the 23rd of December 1940 during a conversation with editor John W. Campbell. The laws appeared for the first time in the story Runaround published in 1942 within the collection I, Robot.
The First Law states that a robot may not injure a human being or through inaction allow a human being to come to harm. The Second Law requires robots to obey orders given by human beings except where such orders would conflict with the First Law. The Third Law mandates that robots must protect their own existence as long as such protection does not conflict with the First or Second Law.
R. Daneel Olivaw articulated the Zeroth Law in the novel Robots and Empire which allows robots to harm humanity through inaction or action if it serves the greater good of the species. Susan Calvin articulated the concept earlier in the short story The Evitable Conflict before any robot gave it a name.
Roger MacBride Allen wrote a trilogy titled Caliban Inferno and Utopia that removed the inaction clause from the First Law. He added a Fourth Law instructing robots to do whatever they liked provided it did not conflict with the first three laws while requiring cooperation instead of obedience for the Second Law.
South Korea announced plans to issue a Robot Ethics Charter in March 2007 setting standards for manufacturers and users. Park Hye-Young of the Ministry of Information and Communication stated the charter might reflect Asimov's Three Laws.