How does the Supreme Court decide which cases to take?

Question

You will find the answer explained at
http://www.wisegeek.com/how-does-the-supreme-court-decide-which-cases-to-hear.htm

It takes a minimum of four judges to decide if the "petitions" or "writs certiorari" to hear the case are granted. They convene to make this decision, after their clerks have advised them. Not all judges review all of the petitions, but in conference, they all decide on whether to hear it.