Insomniac Games has confirmed on their Twitter, that Resistance 3 will be released in 2011. The game won't be on display at PAX early September, where Insomniac are focusing on Ratchet & Clank: All 4 One.
Resistance 3 isn't perfect: but its faults are few enough that we'd recommend this death-ridden jaunt across America to anyone clutching a PS3 controller this autumn."