I went to an AT&T store here in Miami lined up about 11pm or midnight when they were going to open at 8am.
There eventually were about 120 or so people in line and I was approximately in the first 20. Around 7:00 am or so a store manager came out and used a blackberry to verify everyone's upgrade status. They also asked everyone what capacity phone everyone wanted and also what color(if I remember correctly). They then handed about 80 people a little card with each buyer's preference. This meant they only had 80 phons available so far.
The store finally opened and they let 3 people in the doors at a time to completed their purchase and buy accessories.
At the time, I was on my parent's account, which i solely used, and when I went to buy my phone, I wasn't actually an authorized user on the account. I had to go home, get on my Mac and put myself on the account as an authorized user. I went back to the store and they let me in immediately to complete my transaction, which really pissed off people who were waiting in line and didn't see me at the front earlier.
Well, the store sold out of their stock pretty quickly and there were a lot of upset people. This consisted of people who did get a phone but not the color or capacity they really wanted, and people who were in line for hours and didn't initially get a phone.
UPS actually showed up a short time later with about 60 more phones. so some customers were appeased.
All in all, it was a pretty orderly and good experience from an AT&T carrier store.