Wow! Tonight was a wild ride on the online order system... Kept getting the "oops" error and booted out to the main store menu. I kept re-inputting my iPhone selection and cell account information over and over via the web site, to no avail. Simultaneously, I was trying to process the order (AT&T white 32GB) on my iPhone app. Finally, I received a GREEN "Unavailable for Pickup" message (yes, green) from the closest store to me and tried to place the order. To my surprise, it went through and I received the "Thank You" email from Apple a few minutes.
I waited a few more minutes, then went back online and entered my wife's account information for the same phone selection (to verify inventory), and discovered that there were over ten phones in my cart! After deleting all but one, I selected "Pick up" and the phone showed as "In Stock" at the closest Apple store (as well as about five others a bit farther away). In fact, the system still shows them as being in stock...
Hopefully, they were indeed in stock and I'll get the confirmation email in the morning...