Sure Sony has been slow to abandon the ps2, but you can't say that they've haven't been supporting the ps3.
Since launch Sony has developed and/or published these games:
Uncharted: Drake's Fortune
Warhawk
Resistance: Fall of Man
Ratchet & Clank Future
Folklore
Lair
F1 Championship Racing
MotorStorm
Heavenly Sword
NBA '07
NBA '08
Hot Shots Golf 5
...and others.
Seven of those are first party, with the remaining five being second party. And Sony recently acquired Evolution Studios, so I guess MotorStorm would be first party now as well.
1st/2nd party games they have lined up for this year:
LittleBigPlanet
White Knight Story
Resistance 2
inFamous
Heavy Rain
Killzone 2
Gran Turismo 5: Prologue
Socom: Confrontation
The Getaway 3
...and others I can't remember.
And God of War 3 wasn't really announced. Some higher ups let slip that it was in development, which was quite unsurprising, but that's it. It's no different then Nintendo saying that the next Zelda is in the works, or Microsoft mentioning Halo: Chronicles.
