As quoted from GDC 2009:
We got to talk with Todd Stevens of Infinity Ward today, and he had this to say about Modern Warfare 2.

"Modern Warfare 2 is set to release early this November, and will be on the PS3, Xbox 360, and PC. The Playstation 3 is our leading platform for Modern Warfare 2. The PS3 version will run smoother and have slightly better visuals than the PC and 360 version. We've been working on Modern Warfare 2 ever since we released Call of Duty 4 back in 2007. We would like to thank everyone who is still with the Call of Duty 4 community. We will be releasing more information throughout the coming months, so be patient."
http://community.eu.playstation.com/playstationeu/board/message?message.uid=7403275#U7403275

http://forums.gametrailers.com/thread/ps3-lead-platform-for-modern-w/779924

Yes!

Ive been fed up of inferior COD games since the start of this Gen on PS3.
I love you Infinity Ward

"PS3 version runs smoother and looks better than PC version"

Yeah, a random PS3 forum is very credible indeed.

exactly what I thought

Runs better than the PC version?

Bullshit detector at 9000 reading.

Damn, that got my hopes up.
Anyway, I still rekon the PS3 version will at least be on par with the 360 version this time

Well it was on par last time..

i cant say that im really looking froward to this game im not into FPS w/o cover systems but ill have to check this one out to see wat all the fuss is about

its good to see that finally 3rd partys are accepting the ps3 for lead platform now

better than the PC?? Hurraz!!

call of duty 4 wasnt as good graphicaly on the ps3 as the 360 version, hopefully they will be the same this time, also hoping infinity ward can actually put some effort into the single player campaign this time. because the call of duty 4 campaign was horrible and short.