C-SPAN is covering today's proceedings:
A three-judge panel on the Ninth Circuit Court of Appeals in San Francisco will hear an oral argument today on California’s ban against same-sex marriage. In the November 2008 elections, California voters approved Proposition 8, an amendment to California’s Constitution that limits marriage to a man and a woman. The Court will decide if a lower court rightly struck down the voter-approved ban as unconstitutional. ...
The oral argument will be divided into two hour-long sessions with a brief recess in between. In the first hour, the parties will address each appellant’s standing and any other procedural matters that may properly be raised. In the second hour, the parties will address the constitutionality of Proposition 8.
C-SPAN's schedule says that the oral arguments will be broadcast live from 1 pm to 3:30 pm ET.