The new iPad went on sale in the United States on Friday, with Apple fans queuing at the company's stores across the country to be among the first to snap up the coveted tablet computers.

Apple began selling the iPad 2, which was unveiled by chief executive Steve Jobs last week, as sales opened online overnight and at Apple's 236 US stores starting at 5.00 pm (2200 GMT).

Estimated shipping times for iPads ordered at Apple's online shop went from a few days to a few weeks, indicating strong demand by people who didn't want to face queues at real world stores.

"I suspect they will sell more iPads this time around than last time around," Gartner analyst Van Baker told AFP.

"I am not seeing much shape up in the form of competition, so I have to continue to believe they are going to be pretty dominant."

A line of people, including some who camped out overnight swathed in rain gear and equipped with chairs and big umbrellas, formed around the block outside Apple's Fifth Avenue store in New York City.

First in line was Hazem Sayed, an applications developer who had purchased his coveted spot from Amanda Foote, an entrepreneurial 20-year-old from Florida who staked her claim outside Apple on Wednesday, then auctioned the place on Craigslist and by word of mouth.

"It went from $150 to $600 in about 10 minutes," she said. Finally Sayed came in with the winning bid: $900.

Sayed said he'd be immediately taking his new iPad 2 to a business meeting in Dubai where he would use its technology for mounting interactive presentations. "I'm going to buy two iPads. If I could I'd buy four," he said.

Many others in the crowd were foreigners seeking to take advantage of an opportunity they won't have in their own country for a while.

The iPad 2, which is one-third thinner, nearly 15 percent lighter and faster than the model released in April 2010, will be available in around two dozen other countries later this month.

Mingda Zhong, 18, a student from Nanjing, China, said that even the original iPad is rare at home. "You cannot buy the iPad 1 very easily," he said.

"Most Chinese do not have it."

About 50 people near the head of the long iPad 2 queue of outside the apple store in downtown San Francisco were there for a company that evidently intended to send the tablets back to China for resale at hefty mark-ups.

Second in line was James Almeida, a 24-year-old college student who resisted the original iPad but showed up at 4:00 am to sate his longing now that the second-generation model is available.

"I decided that the iPad is not something that anyone really needs, but if you have it, it's awesome," Almeida told AFP. "This is the only product I've seen that has created its own need, which is amazing."

Besides the size and weight, the other major improvement to the touchscreen tablet computer is the addition of front- and rear-facing cameras that allow users to take still pictures and video and hold video conversations.

Apple sold 15 million iPads last year, bringing in $10 billion in new revenue and creating an entirely new category of consumer electronics devices.

Dozens of other companies have been scrambling since then to bring tablets to market, most of them relying on Google's Android software, and Apple is hoping the iPad 2 will keep it a step ahead of its rivals.

But with the exception of the Galaxy Tab from South Korea's Samsung, rival tablet-makers have enjoyed little success.

"So far, it's looking pretty rosy for Apple," Baker said.

Technology research firm Gartner is forecasting sales of 55 million tablet computers worldwide this year and another research firm, Forrester, said Apple has little to worry about for now.

"Competing tablets to the iPad are poised to fail, which is why we're forecasting that Apple will have at least 80 percent share of the US consumer tablet market in 2011," Forrester said.

The iPad 2 received mostly praise from the influential technology columnists who adored its power, beauty, sleekness, and "eco-system" of applications for work or play.

More than 65,000 applications have been created for the iPad, while there are currently only about 100 crafted for tablets running Android.

The iPad 2 is selling at the same prices as the original iPad, ranging from $499 for the 16-gigabyte version to $829 for the top-of-the-line 64-GB model.

The iPad 2 will be available on March 25 in Australia, Austria, Belgium, Britain, Canada, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Luxembourg, Mexico, the Netherlands, New Zealand, Norway, Poland, Portugal, Spain, Sweden and Switzerland.