Well, previews runs about 3 months ahead, depending on what you're ordering. They keep saying “fall”, which to me means “August at the earliest”. But if they were shooting for August, then it would have been in this month's previews, and it wasn't.
My gut feeling is that now that they've announced, it means they're ready to solicit too…which means I'd start looking for it in next month's Previews. Next month's previews means September.
Like I said, just my thinking, not fact…but I'll be really surprised if I'm wrong.
**edit**
An alternative thinking would be that they're holding off for October because of that whole Halloween thing…but I'm gonna hold to September.