I tried a few minutes ago and couldn't get it to work. I only tried it because of people mentioning weird stuff about their orders. Mine went through after a few minor glitches in the wee hours of the morning. I've got to make sure I don't get charged thrice!
This is probably some sort of slamming problem that has spiraled out of control. Apple may have underestimated demand, especially with AT&T's lower data prices, and probably had a surge of people hitting all websites involved. I doubt this would've been as much of a problem had it not all involved tapping into AT&T's servers.