In Hawaii, Gamestop did a pre-order on Sept. 18th as a "test-run" before the other stores for both PS3 and Wii. The catch was you had to turn in $50 worth of used stuff to get a pre-order...no cash taken. One Wii and PS3 pre-order per customer, $50 worth of trade ins per order.
Simple. Even more simple was you could literally turn in anything they sold...crap DVD's, controllers, etc.