Pre-orders are only shipping now, so I wouldn't expect any US folks to have it immediately, but Gamecraft(er?) Miniatures just started carrying the line. Brigade Games also carries some Battlegroup stuff. You can find random sellers on eBay but often for far over MSRP.
I'm very interested in Pacific as the next theater I'd pursue...but sadly the lack of quality plastic kits in 15mm for major forces there kills that enthusiasm dead. Even if I decided to cope with metals in 15mm, I won't pay Flames of War/Battlefront prices for sculpts from 2005, etc.
I'd hope that changes at some point, but Battlefront won't randomly be doing full plastics for the Pacific and PSC would have likely announced something (even a teaser) if they were going to launch a line along with the book, etc. Shame, but I can occupy myself with other stuff for a bit.