The Supreme Court ruled that the California Prop 8 challengers did not have standing to challenge the ruling of the lower courts, and thus the trial court ruling making Prop 8 unconstitutional stands. The Court appears to have narrowly tailored this decision to California and Prop 8, and not in making a sweeping decision that recognizes same sex marriage nationally.
With the ruling in the Prop 8 case, and the DOMA ruling, both sides of the marriage equality issue claim victories and defeat. Those on the side of marriage equality would ideally liked to have seen a sweeping decision, much like Roe v Wade, but the Court was not prepared to make that leap.
So for now, gay couples married where same sex marriage is legal are entitled to federal recognition of that marriage, and in those states where same sex marriage is not legal, their laws still stand.
Sounds like not that much of a change. The battle on both sides shall continue on!