As was revealed during their panel at San Diego's Comic Con this weekend, Wizards.com has all the info about the second set in the Innistrad block is 'Dark Ascension.' The subtitle 'Command the Night' and will be a 158 card deck. This is only slightly larger than Mirrodin Besieged was at 155 cards.
Prerelease Events: January 28-29, 2012
Release Date: February 3, 2012
Launch Parties: February 3-6, 2012
Game Day: February 25-26, 2012 March 3-4, 2012
Official Three-Letter Code: DKA
Twitter Hashtag: #MTGDKA
Design Team: Mark Rosewater (lead), Jenna Helland, Zac Hill, Graeme Hopkins, Matt Tabak
Development Team: Tom LaPille (lead), Mark L. Gottlieb, Zac Hill, David Humpherys, Ken Troop
Update: On Sept. 2nd, Wizards announced a change in the date of the Dark Ascension Game Day from March 3-4 to February 25-26.