I have mixed emotions about Apple moving online iPhone pre-orders from a weeknight to a weekend; on the one hand, this means that many of us won't be getting turnt on a Friday. On the other hand, there won't be any bleary, dead-eyed workers collapsed at their desks the next morning. You win some, you lose some.
Regardless of how you feel about Apple's weekend pre-order party, though, there's one thing you want to do right now: open the Apple Store app on your iOS device. Look for this blue bar across the top:
By tapping it, you'll be able to pre-fill your carrier information to check your upgrade eligibility — that way, you won't have any anxious moments at 3:01AM Eastern tonight as you hurriedly punch in all that info while you can literally feel the model you want slipping away from you. Historically, people have sometimes had better luck quickly ordering through the Apple Store app than they have through Apple's website, so the app should probably be your Plan A.
Update: Read the iPhone 6S review.
Of course, by tipping you off to this, I've worsened my own chances of getting the rose gold 6S Plus I need in my life, so I'm debating just trashing this post and pretending we never had this conversation.
Good luck out there tonight, folks.