When I beat SS I decided to go back to Gamestop and pick up HG for gits and shiggles, then they offered reservations for Black and White. Definitely couldn't resist and I hope there's a midnight release for it as well.
Ordering it in store is the way to go. I ordered SS online from
amazon, and it took 2 weeks to come in after the release date. I might as well have not bothered, because I just picked up a copy of HG from best buy on the release date.