This article in Educational Leadership (2004) by Richard DuFour is a useful introduction to PLC. In 2009, 51 schools in Singapore were on a pilot project for PLC schools. In 2010, the numbers doubled. By 2012, all Singapore schools should be PLC schools.
See the link on the right for the full article.
Briefly, the three big ideas in PLC are (1) to focus on student learning (2) to develop a culture of collaboration and (3) to focus on results.