iPhone is available but it seems like its launch isn’t so smooth as Apple and AT&T has hoped. While the majority of users experienced quick activation it seems like some of them are receiving the message "Your Activation Requires Additional Time to Complete," and still not receiving successful notices after up to 20 hours.

Apple support forum is already filed with hundreds of messages from the users who are experiencing problems with the activation and some of them also reported problems while trying to transfer existing cell phone numbers, especially from other mobile carriers.

:It could be worse, my iPhone won't let me transfer my number from TMobile. It just says "The phone number you entered cannot be transferred. You must uncheck the transfer number option and clear the information in the text fields to continue." Worse off, I want a good explanation for this, not some dinky you have to tell everyone you know what your new number is.. ugh... and yes i have triple checked all my info.” wrote a user on Apple forum.

AT&T doesn’t seem to a have a real solution and meanwhile some users discovered how to make the activation.

“17 Hours into this, I have been unable to port my Verizon Phone Number to the iPhone. I called customer service, you know, the 877.800.3701 number.Now, let me first say this - if you get hung up on, at&t is aware of this, it's a glitch apparently. I kept calling and got someone within 30 seconds of holding. He said there were 0 people in queue, and they keep getting dropped calls.

Anyways, the solution. If you are porting, CANCEL it over the phone. AT&T will reverse, and you will get an email immediately canceling the activation.

Reactivate, but do a NEW line of service, do NOT port. At&t states that you can port after the madness dies down. I ran through the ropes, my phone is now activated with a different number, for now. I have my old number forwarded, so calls will route to the iPhone. Also, I am already receiving calls on the iPhone, it took about 7 minutes total...” wrote another user on the same Apple forum.

According to AT&T the company is trying to find solutions for every issue as soon as possible. "The vast majority of activations are going through in a matter of minutes, as they're designed to," said AT&T spokesman Mark Siegel on Saturday, quoted by Computerworld.com. "Have there been instances where customers have experienced delays? Yes. We're trying to resolve them as quickly as possible." he added.

AT&T and Apple didn’t disclose how many iPhone’s were sold so far or how many users had activation problems with their new gadget.