After standing in line for hours on Friday to buy the new Apple iPhone, some users were forced to wait even longer to activate the phones, while others found the store shelves empty and will have to wait another week for their phones to arrive in the mail.

On Monday, staff at an AT&T store in Boston said they had run out of iPhones on Friday night while a line of customers still snaked out the door. People at the back of the line purchased their phones through "direct fulfillment," and will receive their phones through the mail in three to seven days, the store said.

AT&T declined to release sales figures, but said that virtually all of its stores have sold out of iPhones. Over the weekend, AT&T referred disappointed customers to the Apple website, but now says it plans to begin selling iPhones through its online store as well, said AT&T spokesman Michael Coe. He did not give a date.

AT&T downplayed the reported activation delays.

"The vast majority of iPhone customers have completed the activation process in just a few minutes, as planned," Coe said. "Only a very small number of customers who purchased an iPhone this weekend are experiencing issues with activation and all our energies are focused on clearing up these difficulties just as quickly as possible."

Apple did not return calls for comment.

Some analysts blamed the delays on heavy user traffic.

"AT&T's servers were slow due to the mass number of sign-ups in the first few hours with credit checks. This may have delayed some purchasing of iPhones," said Shaw Wu, an analyst at American Technology Research, in his Monday report to investors.

Other customers experienced delays when they tried to switch to AT&T from other carriers, he said. Still, Wu upgraded his stock estimate for the company, and predicted the iPhone would become the fastest-selling product in Apple's history. Within three years, Apple could become one of the top smartphone vendors, changing the competitive landscape of that industry, he predicted.

Even customers who took their iPhones home on Friday faced potential delays in activating them. Users who registered their phones on iTunes aw a warning that the process could take between 24 hours and 48 hours, said Craig Henry, a 32-year-old IT administrator at a law firm in Massachusetts.

Henry's wait lasted for three hours, when he received an email confirmation that his phone was activated. However, he soon faced another challenge when he tried to transfer his address book to the iPhone.

"The hardest part for me was transferring my phone numbers, because I was on Verizon and I didn't have the software to keep the numbers on my PC. So I spent an hour typing in about 150 numbers," he said.

He also had to get accustomed to the touch screen interface, which relies completely on finger drags, flicks and pinches instead of using hard keys.

"It takes a little bit of getting used to. But the typing works fine; I was sending text messages all day on Saturday," Henry said. "When you're in the contacts sheet, you run your finger across the screen - kind of like flicking a marble - and it scrolls really fast, or you can drag it and scroll slowly."

Many users were concerned about iPhone battery life, an issue that Apple tried to address on 18 June by upgrading the original battery before the product even launched. Still, Henry visited an Apple store on Saturday to buy a second charger so he could power his iPhone both in his home and his office.

Despite the hurdles of learning to use his new gadget, Henry said he suffered no buyer's remorse.

"I was out on Saturday night, and everybody knew I had it and wanted to touch it," Henry said. "They made a little fun of me for waiting in line so long, but I don't think the wait was too bad. When people see it, they're amazed by it."