More episode titles have been revealed. Only the finale is yet to be announced:
S02E01: The North Remembers
S02E02: The Nightlands
S02E03: What Is Dead May Never Die
S02E04: Garden of Bones
S02E05: The Ghost of Harrenhal
S02E06: The Old Gods and the New
S02E07: A Man Without Honor
S02E08: The Prince of Winterfell
S02E09: Blackwater
I would be very happy if the finale was titled
A Clash of Kings!