Possible, but given that ME 1 and by extension ME2 (and possibly ME3) were built on an engine with the 360 in mind, would it really be worth the additional costs to port and take the risk that they won't sell enough copies to make their money back?

Also, I'm guessing MS paid for exclusivity, would Sony be able to match that if sales fall short?

I don't think Microsoft owns the IP so it could well go on the PS3 as well. It would probably sell a solid million - million and a half.

Maybe but I doubt it will sell..... Just like Bioshock.
I think EA already learnt the lesson from Take Two.

Possible? Of course.

Probable? I doubt it.

I´d say it´s possible, but unlikely...as for MS being the publisher, that didn´t stop Ninja Gaiden 2, so there are ways around it.

mass effect 2 will come out on ps3 6 months later than 360 version.

I think they got some sort of Exclusivity deal with Bioware for Mass Effect Franchise, its their KOTOR this generation i doubt they would let it go to PS3 as well. So i think ME will just stay where it is, especially it does sell well enough there, and the 360 is a better market for WRPG's.

Micrsoft don't own the Mass Effect IP so anything is possible - I doubt ME 1 will come out on PS3 but theres a much higher chance that ME 2 will only be timed exclusive on 360

The fact that Microsoft and Bioware announced a trilogy from the get-go makes me think there is probably some kind of deal for all three in place.

Who knows, but i have the first one on the 360 and it is a pretty good game once you get the hang of the controls!