Very depressed that there is still not news on this.
I bought Season 3 in October 2010 and still only completed episode 1 as I just don't get into PC gaming anymore.
The first two seasons on the Xbox I couldn't leave alone, had to make a point of only doing one episode a day. I still go back on them now and again trying to get the last elusive achievements.
I would happily buy Season 3 again on Xbox. I'm starting to wish I had gotten it on PS3 now, might still have done if they had made it compatible with Remote Play so I could play it on my Vita. But I hate the PS3 controller.