Apple has started selling the first iMac computers that are powered by Intel's dual processor chip.
Intel CEO Paul Otellini joined Steve Jobs on the stage
The announcement about the availability of the Intel-powered computers was months ahead of the schedule Apple announced in 2005 for the new range.
Apple boss Steve Jobs also launched a newly branded laptop called the MacBook Pro which also uses an Intel processor.
The new generation of iMac would be two to three times faster than the current iMac G5, he said.
The MacBook Pro would be four to five times as fast as the current PowerBook G4, Mr Jobs told Macworld in San Francisco.
The new laptops will not ship until February but the iMacs are available immediately and the price - starting at $1,299 (£929) - will remain the same.
It was widely expected that Apple would use the Macworld platform to announce that Intel-based computers would ship.
The rest of the Mac family will shift to the Intel dual-core Duo chip during the course of the year. It represents the culmination of a fast-moving collaboration between Apple and Intel, and both Steve Jobs and Intel chief executive Paul Otellini were on stage to pat each other on the back.
The shift to Intel was first revealed last year. Previously, Apple machines were powered by PowerPC chips made by IBM and Freescale.
Slice of iLife
The keynote speech from Steve Jobs at Macworld concentrated, as expected, on computers rather than digital entertainment.
In fact, the only announcement of note for its growing family of iPods was a remote control with FM radio capabilities.
It will allow users to skip tracks and adjust the volume of their iPod without having to have it in their hand. It will also enable them to listen to FM radio stations.
It will be priced at $49 (£35).
The main slice of Mr Jobs' presentation was given over to updates that Apple has made to its suite of digital lifestyle applications, iLife.
iPhoto gains a new application to allow people to take part in what Mr Jobs described as photocasting - basically allowing people to subscribe to a feed of photos from someone else which will automatically update every time new photos are added.
There was a new application for iLife which will allow users to build websites to show off all their rich media.
"Everyone wants to share music, photos, blogs and podcasts over the web and there are applications out there that let you build websites," said Mr Jobs.
"But the easy-to-use ones often build ugly websites so we have created one that is easy to use and builds beautiful websites."
Dubbed iWeb, the application will ship with all new versions of iLife. The price of the package - at $79 (£55) - will remain unchanged.