Apple is set to unveil a new ultraportable laptop on Jan. 15, according to the army of online pundits dedicated to tracking the iPod maker's every move.

The Macworld Conference & Expo, the annual jamboree dedicated to all things Apple, is still a week and a half away, but already the Web is buzzing with details of expected new products and business partnerships — including a series of deals with Hollywood studios under which Apple will enter the online-rental video market, and a rumored upgrade to the iPhone that would give the device a GPS-type function.

However, the expected launch at the San Francisco-based event of a lightweight, super-thin laptop — a device seemingly pitched between the iPhone and its current MacBook line of computers — is kindling the greatest interest among Apple aficionados.

• Click here for's Personal Technology Center.

Suggestions that such a "tablet"-format machine, said to be fitted with flash-based memory and an external disk drive, is imminent were stoked last month when, an industry news site, revealed that Apple had secured a supply of 13.3-inch LED backlight units, used for ultraportable laptop computer displays, from Taiwan.

Commenting on a proliferation of more detailed reports in recent days,, a closely-read blog, said: "While anything is obviously possible, it sure seems like the safe bet is that Apple will unveil some form of ultraportable laptop at MacWorld in a couple of weeks."

Mac Rumors, another Web site, said it had received "reliable confirmation" on a number of features of Apple's forthcoming "sub-notebook" including the omission of an internal optical drive to cut down on size and weight.

"Instead, Apple is said to be offering an external optical drive with the sub-notebook. This detachable external drive would allow customers to read/write from CDs or DVDs as usual, but would allow users to leave this extra bulk at home when on the road," the site said.

It added that Apple is also expected to announce upgrades to its current line of MacBook and MacBook Pro laptops.

The rash of speculation suggests that Apple is fighting a losing battle in its efforts to clamp down on the leaks and speculation that accompany its product launches.

Last month it reached a legal settlement with ThinkSecret, a site it had sued for allegedly leaking industrial secrets.

[ThinkSecret, started by a 13-year-old boy eight years ago, shut itself down as part of the settlement, but was allowed to keep its sources within Apple confidential.]

The addition of a new ultra-portable machine would fit with Apple's recent thinking. The iPhone, which comes equipped with a fully-fledged Web browser, was heralded as much as a miniature computer as a telephone when it was revealed at last year's Macworld Expo.

Apple also has close links with Google, which is bidding for a spectrum license in the U.S. that could be used to roll out a wireless broadband network.

Rival Internet players such as Yahoo, meanwhile, believe that more people will soon access the Internet through mobile devices than they will through conventional personal computers.

The launches of iPod models, and more recently of the iPhone, have garnered the bulk of the media coverage lavished on Apple, but the company's computer business has also made great strides.

In its latest financial statement, Apple said that it sold a record 2.16 million Macintosh computers in its fourth quarter, 34 percent more than for the same period the year before.

Of those, sales of laptops rose 37 percent, contributing to a 67 percent leap in profits to $904 million.

The news helped push Apple shares above $200 for the first time late last month.

Recent surveys suggest that the company has since continued to gain ground on Windows-based PCs.

According to Net Applications, a group that tracks Internet use, more than 7 per cent of visits to Web sites in December came from computers running Apple's Mac OS X, a record high.

Computers powered by Microsoft's Windows operating system — including, presumably, some Intel-based Macs "dual-booted" into Windows — still dominated, however, accounting for more than 90 percent.