It will be released at May2008 you may find more information about the PC version in Bioware Forums
Yes, it has already been released for PS3, and when Mass Effect 3 comes out in December 2011, it will be for XBOX, PS3 and PC.
No. That's a single player game.
No mass effect 2 will only be on xbox 360 and PC
BioWare, the developer of Mass Effect has confermed Mass Effect 2 to come out in 2010.
Both versions are mostly the same, although the PC port of Mass Effect is a bit more improved than the Xbox 360 original (Load times, interface, etc)
You can buy a Mass Effect 2 Key for PC on Steam, Origin, or G2A.com.
No, only Xbox 360 and PC.
is a rpg/fps game for xbox360 and PC
Mass Effect for the PC and 360.
Currently, it is out for PC and Xbox 360
Xbox 360, PC and PlayStation 3
Yes January 2012