I sent an email in to sales to ask for a clarification about this. The word I got back was that they will be shipping the books "over the next couple of weeks". Which says to me that they could be here anytime between tomorrow and a month from now. I'm glad they are taking the time to fulfill the preorders, but it sounds like we've got a few more weeks yet to go.
Disclaimer: I am in the US, so those closer to the source might be getting them sooner.