From Prop 8 Trial Tracker:
The Supreme Court docket page for Hollingsworth v. Perry, the Prop 8 case, has a new notice that the case has been “DISTRIBUTED for Conference of September 24, 2012.” The September 24 conference is the first time this term that the Justices will meet privately and look at petitions for certiorari to decide which cases they will accept for review. Usually, the Court announces its orders from conferences on the Monday following the conferences, however if they do take up the Prop 8 case on September 24, they could announce as early as the next day whether the full Court will review the case. It takes four votes to grant review.
If the Court denies the petition, the Ninth Circuit Court of Appeals’ decision stands, and Proposition 8 will be invalidated, though the case won’t set a nationwide precedent. If they decide to review the case, they’ll reach a final decision on the merits at the end of June 2013.
The Court could also potentially ‘relist’ the case for a later conference. This would mean instead of making a decision at the September 24 conference, the case would be held and listed for a subsequent one.