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.
Also distributed for the September 24 conference is Windsor v. USA, challenging Section 3 of the Defense of Marriage Act. Windsor was petitioned to the Supreme Court for review before judgment at the Second Circuit Court of Appeals, where oral arguments are currently scheduled for September 27.
SCOTUSBlog lists the Golinski v. OPM and all of the Massachusetts DOMA petitions as distributed for the September 24 conference, however, the Supreme Court docket page for those cases does not reflect this yet.
h/t Kathleen Perrin for this information
UPDATE: FYI, Jon Davidson, legal director at Lambda Legal comments (at P8TT):
While it of course is possible that the Supreme Court will decide whether or not to hear the Perry case at the September 24th conference, they may well wait until they decide whether or not to hear the Gill and Goinski cases, which are not scheduled for conference at the moment until October 5th. (I believe SCOTUSBlog is wrong about Golinski; a reply has not yet been filed by DOJ to BLAG's opposition to DOJ's petition for cert. before judgment in that case, so, as the Supreme Court's docket reflects, it has not been set for the September 24th conference. SCOTUSBlog also says that Diaz has not yet been set for conference, but the Supreme Court's docket says it has been -- for September 24th. I think SCOUTUSBlog just go these mixed up.) So, people should not be counting on knowing about Perry on September 25th. It could be we won't know until October 9th at the earliest (because the 5th is a Friday and the 8th is Columbus Day). -- Jon Davidson, Lambda Legal