Apple kicked off this week's Macworld show here with upgrades to its iMac and Power Mac G4 product lines, and a pledge that Mac OS X version 10.1, the first major upgrade to its recently released operating system, will ship in September. Apple CEO Steve Jobs pleased the crowd with a demonstration of some of version 10.1's improvements, including faster application launching, more elegant windows resizing and a moveable dock, improved networking capabilities with machines running Microsoft Windows, and the ability to burn data CDs from the Finder. Jobs also introduced new hardware, including three Power Macs with processor speeds running at up to 867MHz. The new computers are housed in silver-colored "quicksilver" cases. Priced at £2,499 (plus VAT) and scheduled to ship in August, Apple's new high-end model will be a Power Mac G4 featuring dual 800MHz processors, 256MB of RAM, a 80GB hard drive, and a SuperDrive, a CD-RW/DVD-R (CD-rewriteable/digital versatile disc-recordable) combination manufactured by Pioneer and adopted by Apple earlier this year for use in its high-end machines. Two new Power Mac G4s are currently available. Apple's £1,799 (plus VAT) machine has an 867MHz processor, 128MB of RAM, a 60GB hard drive, and a SuperDrive. For £1,199, the company is offering a Power Mac with a 733MHz processor, 128MB of RAM, a 40GB hard drive, and a CD-RW drive. Apple made less radical updates to its aging iMac product line, trimming prices and upping iMac processor speeds to 700MHz. Two new iMac configurations are now available: an iMac with a 500MHz PowerPC G3 processor, 128MB of RAM, and a 20GB hard drive; and an iMac with a 600MHz processor, 256MB of RAM, and a 40GB hard drive. A 700MHz model with 256MB of RAM and a 60GB hard drive is slated for August availability. Each of the new models includes a CD-RW drive. Apple's last major Macworld New York hardware debut was short-lived: The Power Mac G4 Cube, introduced last July, was scrapped earlier this month because of poor sales. Jobs devoted the first hour of his keynote to touting the Mac OS X, released in late March. A parade of Macintosh developers took the stage to demonstrate how their applications are optimized for the operating system. A representative from Quark previewed its upcoming new release of its QuarkXPress publishing software, which will allow easy print-to-Web content transitions, while Connectix showed off its forthcoming Virtual PC for Mac OS X software.