BioWare's community coordinator and Mass Effect team member Chris Priestly recently commented on Wedbush Morgan analyst Michael Pachter's assertion that EA-owned BioWare will make Mass Effect for the PS3. In his message posted in the official BioWare forums, Priestly revealed that BioWare "could" make Mass Effect for the PS3, but they are not working on the PS3 version currently.
Here is the relevant snippet of Priestly's comments -- in which he highlighted the word "could":
"Sorry folks, this is just another rumor at this stage. *Could* BioWare make Mass Effect for the PS3 (or the PC, or some other platform) in the future? Yes we could, but we are not working on a PS3 version currently."