Earlier this week, the DC blog posted this image by Ivan Reis.
Comic Book Resources believed it may be a redrawn image for DC's 75th Anniversary variant covers. But instead it was one of a number of alternative universe versions of comics that appeared in last night's finale of Fringe. If you are spoiled by seeing cool comics covers look no further, but that's the only spoiler you'll see here.
So that's Red Lantern/Red Arrow #76, The Dark Boy Scout Returns by Frank Miller, The black polybagged issue of Batman #75 featuring his death, a different cast for the Giffen/DeMatteis Justice League #1 and a different death for Crisis On Infinite Earths #7.
Look for the DC blog to give all the issues in better resolution later today,