Update 2/6: Microsoft is sending out download codes to those who purchased the season pass for The Wolf Among Us on XBLA. Check your Live inbox for the message. If you haven't received yours yet, you should be getting it soon.
Update 2/5: It's out on XBLA and on PSN in Europe now too. There's apparently a problem with season passes on XBLA, where the system will not let you download episode 2 if you purchased a season pass. Do not click to buy episode 2, as you will be charged twice. Microsoft updated their Xbox live status page stating that they are working on it now, and should have a fix out by tomorrow.
Update 2/4: It's out on the Telltale Games store, Steam, and on PlayStation Network in North America now.The Telltale Blog has just been updated with release dates for The Wolf Among Us: Episode 2 - Smoke and Mirrors.
It will be released on February 4th for PC, Mac, and PSN in North America, and on February 5th for PSN in Europe and XBLA. The iOS version will be released next week as well. The Vita version won't be releasing at that time, as there's still no word on the Vita release of episode one (nor is there any word on the Vita version of The Walking Dead: Season Two - Episode 1 for that matter).