Adding my experience..
Just to add my experience for anyone following this thread, wondering how the process goes or how long it might take. And FWIW, my contract is not up until June 17 2012.
#1.
iPhone4 purchased from a third-party, after I lost my original (on-contract) phone. Used the web chat, gave IMEI. Agent asked origin of phone (Apple, eBay, AT&T activation/discounted rate, etc). I told her I thought it was from Apple and I paid full price - as I wanted to see if they would take my word or ask for purchase verification. She said she would need proof of purchase, but would go ahead and submit the case processing - however, if I didn't fax PoP within 48hrs it would be canceled. Ok, no problem, I said. [At this point, I figured I would just try again with a new agent via phone/chat after the 48hr window passed, since obviously I don't have an Apple Store receipt].
What's interesting is that when I went to check status on imei.info a few hours later -- it says it is
"Sim locked: NO" So, either the phone has been unlocked the whole time that I've had it since Dec '11 (highly unlikely) or for whatever reason the request went thru (quickly) WITHOUT them verifying my proof of purchase. I would obviously like to get my hands on a non-AT&T SIM to be 100% sure, but I don't see why the imei.info would not be accurate.
#2.
iPhone 3GS, off-contract, been in my drawer collecting dust. Decided to call this time, as some report with calling that it seems to happen instantaneously whereas for the chat request (see #1) I was quoted up to 2wks for it to actually happen. First agent I spoke with transferred me to AppleCare - and then vacated the line! [WTF?] Since I'm waaaay past the warranty and phone support, AppleCare asks if I want to pay the $29 support fee - I'm like "Uhh, no, why did they transfer me to you in the first place.....from what I understand it's a request made by AT&T and shouldn't involve AC" So I quickly hung up and called back to get another agent. This time, I speak with someone who seriously acts like he's never done the unlock routine/request before. It went smoothly without any issue though - he verified IMEI, made sure I wasn't past due, etc etc (going down his checklist of requirements) and THEN transfers me to tech support (I thought I pressed 6 to speak directly to tech support in the first place) and this guy basically verifies the unlock is happening now, so all I need to do is backup and restore. Done.
Just a lesson in how inconsistently trained/informed that CS agents can be.
Lastly, no, please don't PM me to call AT&T and help unlock your phone
