Some details include that it will begin in Spring/Summer of 2013 with Mega Man #24, and a "Wily/Eggman bromance" is in the cards: “Got this little blue guy who’s really bothering me!” “Let me tell you about blue guys!” And for those interested, a downloadable Mega Man comic book app is now available. There isn't much else which hasn't been covered previously, though TSS is working on a video of the Q&A portion, so keep an eye out for that.
In addition, ComicsAlliance has an interview with Archie editor Paul Kaminski about the whole crossover, touching on when they first began the project and the debate he and writer Ian Flynn had regarding how canon this whole thing would be, plus why they're telling it in 12 issues across three books.
Oh, and be sure to click over there for a full look at the image seen above.
Edit: And as Crimson Seiko of Mega Man Monthly points out, it looks like Quake Woman might have a spot here that wasn't afforded to any comic-exclusive Sonic characters. Interesting...