Steve Jobs kicks off Macworld 2008 with the announcement of "the world's thinnest notebook," updates to the iPhone, and more.

Apple is touting its new MacBook Air ultraportable, announced Tuesday during Steve Jobs' Macworld keynote speech, as "the world's thinnest notebook."

The computer has a 13.3-inch, LED-backlit display and the same built-in iSight camera as other Apple notebooks. It has what Jobs says is a full-size illuminated keyboard. The trackpad is "generous," Jobs says, and the computer has multitouch gesture support that expands upon the support already present in MacBooks.

The MacBook Air has an Intel Core 2 Duo processor. The 1.6GHz version starts at USD$1,799, the 1.8GHz machine at USD$3,098.

The new MacBook Air is between 0.16 to 0.76 inches thick and weighs 3 pounds. It will start shipping in two weeks.

Apple TV was designed to be an accessory, Jobs said, but that's not what people wanted. They wanted "movies, movies, movies...So we're back, with Apple TV Take 2." Its screen will feature movie rental options.

Movie rentals from major Hollywood studios are now available from the iTunes Store for transfer to an iPod or iPhone. Standard-definition movie rentals are USD$3.99 for new releases and USD$2.99 for library titles.

During Jobs' keynote speech, Jim Gianopulos, chairman and CEO of Twentieth Century Fox Film, described how studios learn about technology. He then cut to a silhouette photo of Homer Simpson from the old iPod ads.

In talking about Leopard, Jobs announced Time Capsule, which is a "backup appliance" that looks like the Mac Mini or Apple TV; it's basically a wireless access point with a hard drive. This enables consumers to back up their notebooks wirelessly over Time Capsule. An early complaint about Time Machine was that it only worked over wired networks.