My experience
I don't want to sound cynical but it's hard not to think that this was planned. If you short one outlet (AT&T stores) then you get the ongoing hype of "OMFG, the iPhone sold out" while there are still plenty quietly on hand at Apple stores everywhere. And then there's that odd 2-4 week delivery time on the Apple site. Hmmm... something doesn't add up and I'm sure Apple and AT&T's marketing people know why.
I don't think it was planned. I think AT&T is just incompetent.
My experience:
Got in line ~4:30pm, Santa Monica AT&T store on Wilshire (apparently a "flagship" store, and the only one in Santa Monica), about 80 people in front of me. An employee comes out, I ask if they have iPhones for everyone. The employee states smugly, "we have enough."
Line starts moving at 6pm. By this time, there are another 50+ people behind me. As reported, AT&T processing systems bogged down (they use Windows, btw). It takes 3 hours to take care of the first 60 or so people in line. A woman periodically comes out, and repeatedly when asked states, "we have enough iphones."
When I ask if they actually have an inventory count of phones and why the vague answer, she states "we know, but I will get fired if I give an exact number." WTF.
About that time, a woman comes out, stating that they are just about out of iPhones. She looks at the line and points to a guy about 5 spots ahead of me, saying he will be the last to definitely get a phone. I say WTF, how hard is it to count the number of phones then count the number of people in line?"
A few minutes later, she comes out and says, finally, we have 39 phones left, and most of them are 4GB. This after waiting in line for 3 hours.
I state the obvious and say, "why did you make people, who had no chance of getting a phone wait in line for 3 hours?" She again stated that it was company policy. Nice answer.
I should have walked over to the Apple store and got one of the several THOUSAND they had in stock. However, since I had just WASTED 3 HOURS in line, I stupidly waited some more and got a 4GB. Which, when I actually got into the store, was fairly painless, taking about 10 minutes, mostly due to my cingular account (some changes needed to be made). The guy helping me in the store was very efficient.
I'm guessing they had about 100-150 phones, with about a 60-40 split between 8 and 4GB.
BTW, my friend, at another AT&T store, had a very similar experience. He was 4th in line when they said they were out of phones. Then, after complaining, they said oh, we still have some 4gb in stock. WTF.
Summary:
AT&T policy was insane. They could have simply counted the number of phones they had and handed out numbered pieces of paper to people that could actually get a phone. Instead, they purposely made people wait in line, when they had no chance of getting a phone. This on top of prior genius stuff like having no clearcut policy on existing customers until DAYS before the launch, no plan pricing until days before launch, and other stunningly incompetent management of the launch.
The AT&T store manager should be fired. Period.
The AT&T POS system is actually a POS.
As for my phone...
I love it, except I've already run out of capacity. I'd return it and get a 8gb at the Apple store, but AT&T said that there is a 10% restocking fee, those f*ckers.
The case I bought for it is useless. Adds bulk, not much in protection, and poorly designed. And after watching the stress tests on the internet, there appears to be little need for a case. $25 wasted.
Activating the phone for me was pretty painless. After updating to 10.4.10 and iTunes 7.3 (took about 10 minutes or so), the actual activation took about 5 minutes. It actually took longer than it could have since I was looking for more stuff to do... it was that easy.
However, there was a problem with visual voicemail. When someone called me and it went to voicemail, they got an answer that "the number you called is not in service." This required a call to AT&T. Apparently, it is a known problem with routing on their end and they fixed it for me. This took about 20 minutes on the phone. Works fine now.
FYI, this phone rules. It is ridiculously cool. Amazing attention to detail in the software. I mean, just play with the alarm clock or timer. And mind blowingly easy to use... no manuals necessary.