The oral arguments in the effort to overturn Prop 8 ended about a half hour ago, and the hearing has made some things clear, even though final outcome remains uncertain.
Queerty has a good overview of the seven justices that will decide the case and their general political leanings. Much of this was confirmed by what I could see in the oral arguments.
There seem to be two main questions at play here. First, will Prop 8 be upheld? Based on the arguments I would tentatively posit the court will rule this way:
Overturn: George, Moreno, Werdegar
Uphold: Baxter, Chin, Kennard
Unclear: Corrigan
Kennard ruled with the majority last May on the marriage cases, but as the day went on it became clear she does not buy the "Prop 8 was a revision, not an amendment" argument.