"The iPad is here."

With those four simple words, Apple announced on its website Saturday what many have been waiting for since CEO Steve Jobs unveiled the company's latest device in San Francisco earlier this year.

The iPad went on sale in the United States at 9 a.m. at Apple retail stores and some Best Buy locations.

Consumers were able to pre-order the iPad online, and those who ordered early enough will receive it Saturday, either by delivery or in-store pickup. Online demand has been significant, and new iPad orders are not expected to ship until April 12. Apple has limited the number of iPads each customer can purchase to two.

Despite the popularity of online ordering, technology enthusiasts lined up outside some Apple stores as early as Friday afternoon, hoping to be first in line to buy the device.

Some, such as Carlos Herrera of Barcelona, Spain, made a transatlantic effort to be in line for an iPad Saturday morning. Herrera was in New York to get an iPad before it goes on sale in Spain in a few weeks. The 33-year-old school teacher told The Associated Press he wants to show his colleagues how the device can be used in classrooms.

Others are choosing to purchase the iPad instead of other devices designed specifically as e-readers.

Speaking with The Associated Press outside an Apple store in Freehold, N.J., Ray Majewski said he and his 10-year-old daughter came to get an iPad to pursue their interest in electronic books.

"I like the electronic books, and my daughter is really getting into them as well," he said. "I was thinking of getting a Kindle but then said to myself, 'Why not get an iPad, because I can get so much more from that than just reading books.'"

Although not specifically an e-reader, the introduction to the market of the iPad, with its 24-centimetre screen, is expected to heat up e-reader competition.

At the much-anticipated iPad unveiling in January, Jobs described the device as "so much more intimate than a laptop, and so much more capable than a smartphone."

Users can email, store photos, navigate maps and play video games via the device's touch screen.

The iPad runs on a one gigahertz chip and comes with 16, 32 or 64 gigabytes of flash memory storage. It also has Wi-Fi and Bluetooth capabilities and contains an accelerometer, which lets gamers tilt the device, and a proximity sensor.

The iPad ranges in price from US$499 for the basic Wi-Fi model to $829 for the largest Wi-Fi and cellular model. The 3G, or cellular-capable, iPads will not be available in the U.S. until late April.

No Canadian release date for the iPad has been set, but Apple says on its website that the device will be available in Canada in "late April."

While the iPad did gain positive reviews, critics point out that it doesn't have a camera and lacks ports for media storage cards and USB devices. The iPad is also incapable of playing Flash video and cannot run more than one program at a time.

But some fans are merely excited to get their hands on the first version of the iPad, which, like other Apple products, will likely go through a number of changes and updates in the future.

"(The iPad) will define a giant change in how we perceive computers in general and how we deal with them on a daily basis," said San Francisco tattoo artist Max Ackermann.

"It's really cool to be a part of that beginning."