By Kasper Jade

Published: 08:00 PM EST

Apple Computer is on track to introduce the first Macs with Intel processors as early as January, which should help the company avoid any potential sales slow down in the first half of 2006 and appease concerns voiced by shareholders and industry-watchers, AppleInsider has learned.

Although Apple has only committed to introducing the first Intel-based Macintosh systems by mid-2006, extremely reliable sources and a several-month-long investigation have revealed that January's Macworld Expo in San Francisco is being primed as the launch-pad for at least one of the Mac maker's next-generation Intel systems.

Surprisingly, the most reliable information indicates that the iMac and PowerBook -- two of the company's most recently revised Mac offerings -- are targeted to be the first two Mac models to receive Intel processors in January. The iMac and PowerBook are also believed to be Apple's best-selling Mac models, which explains why the company will be upgrading them with Intel processors first and refreshing their associated product lines for the second time in as little as four months.

While it's too early to be certain if the Intel-based 15-inch PowerBook will be completed for its targeted introduction during the second week of January, a company roadmap described to AppleInsider lists both a 17- and 20-inch Intel-based iMac as being "on track" to debut at the annual Macworld Expo conference planned for the same week.

According to sources familiar with Apple's plans, the first Intel iMac won't usher in a slew of new bells and whistles, and instead will be based largely on the design and feature set of the current iMac. In fact, recent rumblings reveal that Apple will reuse the 'media center' iMac enclosure introduced at last month's special event in San Jose, Calif.

Apple service providers who specialize in selling and servicing Macs have told AppleInsider that the media center iMac enclosure and internals are far less elegant than the model it replaces, requiring that technicians gain entry to the machine by removing the face of the computer (rather than the rear). Additionally, the only system component in the computer to remain user-servicable is memory. However, the new design is slightly thinner than its predecessor and appears to run quieter and cooler, they say, making it an ideal fit for use in further revisions.

Aside from a more steady supply of processors, one of the strongest motivations behind Apple's switch to Intel is to obtain chips that could be used to fuel the further development of its laptop offerings, which have seen speed increase of only several hundred megahertz over the past two years.

In a bid to sustain the sales momentum of PowerBooks -- which have continued to be best sellers despite lackluster speed increases -- sources say Apple is working feverishly to ship a 15-inch Intel PowerBook around February, with a likely introduction alongside the Intel iMac during the second week of January.

The 15-inch Intel PowerBook has been described by reliable sources as looking very similar to the company's current offering, but 20- to 25-percent thinner. The model is also expected to pack a built in iSight in the same fashion as the latest iMac G5 models.

Sources say at least one of the two aforementioned Intel Macs appears to be based around Intel's upcoming dual-core "Yonah" mobile processor, which is expected to top-out at 2.16 GHz in its initial rev. However, further processor specifications remain largely unconfirmed at this time.

True to recent rumors, Apple also plans the release of an Intel-based Mac mini, but reliable information indicates that this model will debut closer to the Spring, around the same time that the company revamps its consumer-oriented iBooks with 13-inch widescreens. Like the PowerBook, the new iBook design is likely to be noticeably slimmer than its predecessor and adopt design elements from the iPod and iMac.

"I wouldn't be surprised to see smaller consumer notebook designs that resonate well with iPods," said Jupiter Media analyst Joe Wilcox. "Svelte, sharp Intel-based consumer Mac notebooks could easily appeal to iPod buyers, particularly those people considering a switch from Windows"

The analyst went on to say that Apple is likely to ship Intel chips inside consumer-oriented products -- like laptops -- first, because the company tends to include with those computers most of the software consumers initially need and want. "I see mostly benefit if applications like iLife are ready for Intel processors," Wilcox added. High-end applications not yet compiled natively for the first Intel Macs will continue to run seamlessly -- albeit slightly slower -- via Apple's integral Rosetta technology.

Concerns that Apple could see a sharp fall-off of Mac sales as a result of its transition to Intel chips began to mount immediately following the company's announcement of the move this past June. With Apple providing guidance that suggested the transition period would span 18-months, analysts and even the Mac faithful began to question how the company could expect to sustain strong sales of PowerPC-based Macs after announcing to the world that Intel processors would form the future the platform.

Analysts and some shareholders worried that a significant percentage of consumers would choose to postpone their Mac purchasing plans until the middle of next year -- when the first Intel Macs were expected to debut -- potentially stunting the Mac's recent market share gains and the company's largely Mac-based revenue stream. However Apple, usually one step ahead of its own guidance, appears to have anticipate such fears and has internally planned to circumvent any fall-off in Mac sales by introducing the first Intel systems immediately following the holiday shopping season.

Sources familiar with Apple's Intel plans now believe the Mac maker is striving to complete its transition to Intel chips in the fall of 2006, several months ahead of schedule.