Yeah I've downloaded the Haze demo and of course you could play in co-op mode in story mode with a friend online much like from Halo 3.
However, I dont find it anywhere near as good as Halo 3, sadly. Just a story not very well written with cranky control play and such.
I own Heavenly Sword, Unreal Tourament III, and GTA4 for the PS3.
I know UT3 and GTA4 are on the 360 as well but Heavenly Sword is definetly one of the must owned titles for a PS3 owner. At least that game keeps u busy before God of War 3 comes out. 
