Bioware are already working on Mass Effect 3 even though Mass Effect 2 has yet to hit the shelves. Bioware project manager Casey Hudson had a word with IGN about the threequel,
“We are already at work on Mass Effect 3,” he said, “Building the first bits of the story, putting that together. I think the exciting thing in the final chapter of the series is going to be just seeing where everything goes that we started, with Mass Effect and now Mass Effect 2, you’ll see when you play it, all of these threads keep going. And not only that, all of the choices you’ve made too. You made choices in Mass Effect and you’ll see those in Mass Effect 2. And it just cascades. And people will see that by the time you finish Mass Effect 2, you’ll know that it’s your universe — everything is the way you set it out — and that all of these things get to come to fruition and some kind of ending in the final chapter.”
Mass Effect 3 will be linked to Mass Effect 2 by some choice DLC,
“We don’t have anything specifically announced yet, but we basically plan for DLC pretty shortly after the release of the game and then a pretty intense schedule of downloadable content throughout,” he said. “This is one of the big improvements that we’ve been able to do for Mass Effect 2. Lots of DLC and lots of really high quality DLC that players can look forward to.”
Mass Effect 3 should arrive around 2 years after Mass Effect 2, so January 2012-ish. As to which consoles it arrives on, let the wild speculation begin!