Apple's iPhone launch has been marred by delays in AT&T's phone activation system, leaving some people unable to use their new toy throughout the weekend.

People who buy the iPhone, which went on sale in the U.S. Friday evening, are required to activate it through Apple's iTunes software on their home computer. They choose a rate plan, authorize their credit card number, and the phone should be activated soon after.

Apple has said the process should take only a few minutes for people being assigned a new phone number, and "up to six hours" for people transferring a number from another operator. But for some the wait has been much longer, according to postings on Apple's iPhone message board and elsewhere.

"It has now been 48 hours and my iPhone is still the prettiest paperweight I own," wrote one frustrated user.

"Nightmare indeed," said another. "I've been waiting 11+ hours now. I got the phone after a somewhat reasonable one-hour wait at the Albany, NY store, then spent 4+ hours talking to AT&T and Apple trying to get the thing activated."

Others said their phone was activated in a matter of minutes.

AT&T was not available to comment in Europe on Monday morning, and Apple did not immediately respond to a request for comment.

An AT&T spokesman told the Wall Street Journal newspaper that most activations were occurring in a few minutes, and that the operator was working to fix the remaining issues. An unnamed source told the paper that about 2 percent of users were being affected.

The delays cast a shadow over what appears -- so far -- to have been an otherwise successful launch of the iPhone. The device sells for $500 or $600 depending on the amount of memory on board, plus an activation fee and the cost of the service plan from AT&T, which for now has exclusive distribution rights for the iPhone in the U.S.

When people buy a new cell phone the device is usually activated in the shop where they buy it. Apple and AT&T had billed the self-activation process as "another example of how AT&T and Apple have partnered to bring innovative new features to our customers."

Opinions were divided as to where to lay blame. An iPhone buyer who claimed to work for AT&T said in a message posting that delays were inevitable and not the fault of either company. Thousands were trying to activate their new phone simultaneously over the weekend, the person noted, and the activation requests were lining up at AT&T's network switches "like 30,000 or so people throwing basketballs at one hoop and hoping to make it in."

Others said AT&T should have lined up additional capacity for the activations.

Some said they expected the problems to be ironed out by next week and the incident to be forgotten.

"Activation is going to happen eventually. Why did you invest so much of your time and energy in this?" one person wrote on Apple's board. "Life is too short to worry about this type of thing."

There were some other gripes about the iPhone, although it was hard to tell how widespread issues are. Several users complained that the phone's iPod function stopped playing music when they used it as the same time as the Safari Web browser or Google Maps. Others complained of a bug that caused the e-mails they sent via GMail to appear in their inbox.

Other users, including a person who responded to a posting on the iPhoneFAQ.org Web, said they were unable to transfer an AT&T business account to their iPhone, and were told they would have to start a new, individual account.