Insomniac (known for Resistance and Ratchet And Clank franchises on the PS3 exclusively) have recently announced a multiplatform venture for PS3 and Xbox 360 to take place in a whole new world for players to experience. This announcement comes after a deal with EA Partners.
“Working on Xbox 360 games isn’t the only planned change for Insomniac games. While famous for its ability to produce games on an annual cycle, Price says that Insomniac will give focus on spending “more development time to iterate and polish our games.” According to Price, “all future Insomniac titles will benefit from longer development cycles, which will directly benefit you, our fans.” ”
More at the Source- Joystiq
Sellouts!
No D:
This means less games per year and they won’t be of the same quality
They will be developed with both systems in mind rather than using one system to it’s potential 
From what I gathered..this only means that EA is publishing it..they still have their own rights and Sony still owns Resistance and Ratchet N Clank. It simply means they are trying out this new IP for multiplatform. Nothing really out of the ordinary. Same thing was done with EA and Bungie.
@the second comment
How would this affect quality? Insomniac is known for pushing quality titles in relatively short times and I think they will continue that trend. On the ps3, nothing they did really taxed the system, so now they can focus on pushing both the ps3 further and the 360 along with it. I think this is a win win situation for gamers.
@Mehdi Missous – the article states “Insomniac will give focus on spending ‘more development time to iterate and polish our games.’ ” and that “all future Insomniac titles will benefit from longer development cycles”
That suggests to me that they are going to take longer to develop games