The way Comic-Con logistics work, I wound up attending the "Locke & Key" screening while "The Walking Dead" made a triumphant return to the Con over in Ballroom 20. Fienberg has the blow-by-blow of that in his live-blog of the panel, including the news that the new season will debut on October 16, and now in a 9 p.m. timeslot. (So that AMC can no doubt use it as a lead-in to "Hell on Wheels.")
One of the things that happened at the panel was a screening of a nearly five-minute trailer for season 2, which AMC has wisely already placed online. Take a look, though keep in mind it's not one of those trailers that keeps every upcoming plot point carefully-hidden; it'll tell you a few notable things about where the new season seems to be going.
Also, they used a pull quote from my review of the series at one point, but keep in mind that the phrase was specifically referring to the series pilot, which to my mind was easily the high point of that abbreviated first season.