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Me and My GF both activated at about 730 CST and it only took 2-3 mins. each. I was porting a number and she was getting a new one.
 
I purchased my iPhone at roughly 6:25 PM East Coast time. I was a Verizon Wireless subscriber with a Motorola Q.

From unpacking to activation the whole process took no more than 15 minutes.
 
Roommate and I (both Verizon customers) activated ours around 7:00PM ET Friday and it only took ~3 minutes each. We both got new AT&T numbers -- no porting.

My partner (T-Mobile customer) activated his about an hour later, again with no porting. His activation timed-out in iTunes, telling him to wait for an email. He got the "your iPhone is activated" email about 5 minutes later.
 
Activated around 6:30 friday, took about 3 minutes for it to transfer off my existing AT&T phone.
 
Mine took 3 minutes but I have been with AT&T for 3 years.

Ditto. I was using a Windows machine too.

My wife's iMac was a different story! We knew to update iTunes, but didn't know that Tiger required an update too! Without the Tiger update, the iMac treated the iPhone like a camera and opened iPhoto. Not until we got all the software updated (the Tiger update came out on "iDay" too), did the iTunes set-up feature work.

Then we were scuppered by the AT&T back-log so gave up for the night. The next morning we did a restore on the iPhone and the AT&T activation went through. I was more disappointed with Apple than with AT&T - they should've told us about the Tiger update.

PS I have a buddy who wasn't on Tiger (he had 10.3). He had to buy Tiger and then update it before he could activate his iPhone. That's pretty bad, considering that Leopard is only a couple of months away. He's just had to buy Tiger and won't get a discount on Leopard. That an M$-type gouging.
 
2 mins to activate, and 5 more mins for T-Mobile to port my old number over to it. VERY impressed. Did it at 6.30 on Friday.
 
Wife and I were both porting 3's from Verizon...

Hooked hers up 1st...got the message to wait for email after it timed out(took about 7 hours).

Hooked mine up minutes later...took about 2 minutes to be up and running!

I did inadvertently sign up for TWO family plans (AT&T has since merged the two accounts after a 20min phone call)
 
Still waiting to receive calls & VERY frustrated. I was told by 3 pm I will be up & running. I'll believe it when I see it!!!
 
Activation: Almost immediate
Number Porting: Still waiting (nearly 24 hours so far)

I can make outgoing calls with the iPhone, I just can't receive incoming calls/texts/etc on it. Kinda annoying to carry around two phones.
 
It took under two minutes to transfer my number from Sprint. I was able to call out immediately, and I got my first call into the phone about 1 hour, 15 minutes later. My email telling me my phone was all ready arrived about 5 minutes after my first call.

I guess I got lucky.
 
Activation was pretty much immediate - I was able to monkey with the phone, make calls, etc. right away.

A few minutes after activating, my old phone (via Sprint) quit allowing outgoing calls.

I'm not sure how long it took for incoming calls to be properly routed to the new phone, as I didn't get any on either phone for the evening. (At least, none that I know of. :p)

One friend of mine had no troubles either (existing AT&T customer). Another friend (coming from T-Mobile) had all sorts of hassles, but it's mostly worked out now.
 
Mine took about 2 minutes from my MacBook at around 8pm on Friday, though I was an existing at&t customer. My cousins took about 5 minutes from a different MacBook at around 2am Saturday morning, even though he ported his number from Verizon.
 
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