Like an iPhone

CEO Steve Jobs took the stage to unveil the device, which has been the subject of often dizzying speculation and excitement in recent weeks. "We want to kick off 2010 by introducing a magical and revolutionary product today," Jobs said.

The expectation and hope for many has been that Apple will revolutionize both the e-reader and tablet computing markets, just as it did with the cell-phone and PDA markets through the iPhone.

The iPad features a 9.7-inch (25-centimeter) multi-touch, in-plane switching LCD display; it is half an inch (1.3 centimeters) thick and weighs 1.5 pounds (.6 kilograms). The main processor is a one-gigahertz chip made by Apple, and the device is said to come with 10 hours of battery life when in full use.

Along with 802.11n wireless and Bluetooth, the iPad will connect to AT&T's 3G wireless network. But the data plan is a hybrid of what is offered for phones and laptops already. Users will be asked to pay either $14.99 a month for up to 250 megabytes of data, or $29.99 a month for unlimited data.

The device costs between $499 and $829. The cheapest model will come with Wi-Fi only and 16 gigabytes of flash memory; the most expensive version includes 64 gigabytes of memory and 3G access. The device will ship in 60 days.

During the announcement, Jobs was careful to distinguish the iPad from the netbooks that have grown popular as a cheap alternative to laptops for browsing the Internet and simple computing tasks. Championing the design principles for which Apple is famous, he argued that the new device had to be better than a laptop for Web browsing, sending e-mail, viewing photos, reading e-books, and other tasks.

The interface for the device is similar to that of the iPhone: a multi-touch screen and an on-screen keyboard. The iPad is designed to run all iPhone apps "unmodified, right out of the box," according to Scott Forstall, senior vice president of iPhone software. It can run them either in an iPhone-sized window on the screen, or full-screen at lower resolution. Developers can also modify their applications specifically for the iPad, using a new software development kit that Apple made available today. "We think its going to be a whole other gold rush for developers as they build apps for the iPad," Forstall said.

Jobs and others demonstrated numerous applications running on an iPad. These included games, maps, and versions of Apple's iWork suite, showing word processing, spreadsheets, and presentations.