Ah, thanks for clearing this up. I've used SimplyGames before but never that far in advance of a game's release, and I'd still recommend them for the same reasons you stated.
I stand corrected on Simply Games since my card has just been charged for my Fire Emblem and Astral Chain pre-orders! I guess they are now extracting payment after 21 days. I don't personally mind this at the moment and will continue using Simply Games for the benefit of being able to get games a day early. I will probably revisit my practice of pre-ordering games over a month out however.