DC announced a new weekly series, Countdown, at New York Comic Con that will launch in May after the end of 52.  Numbering will start with #51 and count down to #0 a year later.  According to a DC spokesperson, the title will serve as the 'spine' of the DC Universe books, with the storyline serving as an anchor point for the rest of the line. 

The storyline will be run by Paul Dini, who will serve as the comic equivalent of the showrunner.  Keith Geffen will do breakdowns, working with a variety of artists who will produce the finished art.