Apple confirmed Tuesday what rumor sites have been saying for days: Mac OS X 10.5 "Leopard" will hit store shelves at 6 p.m. on October 26. The Leopard Server OS will be released at the same time.

The much-anticipated 64-bit operating system will sell in a single-user license for US$129, and as a US$199 "Family Pack" that provides licenses for up to five Macs in the same household. Apple will also provide the OS to anyone who purchased a Macintosh from October 1 for a US$9.95 shipping and handling fee.

Apple began taking pre-orders at its online store Tuesday, with a promise that Leopard will be delivered on the 26th, Harry Potter-style.

Apple has claimed more than 300 new features and improvements in Leopard over Mac OS X 10.4 "Tiger," which was released in late April 2005. Among Leopard's most-touted additions are Time Machine, a backup and restore application that also provides document versioning; and the final version of Boot Camp, the dual-boot program that lets Windows XP or Windows Vista run on Intel Macs. Other new features and enhancements include a revamped desktop and redesigned Finder, the Quick Look file preview feature, an upgrade for the bundled Mail and iCal applications, and Spaces, a tool for creating and switching between multiple virtual desktops.

Although Apple pushed back Leopard's launch last April, saying it needed to shift development work to the then-upcoming iPhone, the delay didn't ding Apple, said Ezra Gottheil, an analyst with Technology Business Research.

"It had a slight impact in moving when the revenue will be achieved, but it didn't hurt them at all," Gottheil said. "Things are rolling along really well for Apple, and it's managed to make Leopard into a newsworthy event even though it's late."

Delay or not, Apple CEO Steve Jobs couldn't resist taking a shot at rival Microsoft today. Reprising earlier digs about Windows Vista's multiple editions and the new OS's pricing, Jobs said: "Everyone gets the 'Ultimate' version, packed with all the new innovative features, for just US$129."

Apple will also start selling Mac OS X Server Leopard the same day the client OS comes out; The server version is priced at US$499 for a 10-client license and US$999 for an unlimited-client edition. Leopard Server boasts approximately 250 new features, notably Wiki Server and iCal Server. The latter ties in with Leopard's reworked iCal calendar, which uses the CalDAV standard to debut multi-user calendaring on the Mac.

Analysts have been regularly upgrading their estimates of Apple's financial picture, in part because of the expected bounce that Leopard will give to the calendar year's final quarter. Gottheil would only say that Leopard's sales "will be bigger than I anticipated just a few weeks ago," but others on Wall Street, including Piper Jaffray & Co.'s Gene Munster, have been less reticent about sharing predictions. Last week, for example, Munster said he was pegging Leopard to add US$240 million to the quarter, dramatically up from the US$125 million in revenues that Tiger brought in during its opening quarter.

Chris Swenson of the NPD Group also figures Leopard will outperform its predecessor. "Tiger was the best launch of Mac OS X ever according to our data," he said, "and I expect Leopard to do even better." How much better, however, is up for grabs. On one hand, Swenson said, he wonders how Apple can improve on the 2003 launch of Tiger. "It was such a successful launch," he said. "Apple had a well put-together strategic plan in terms of promotion and training and support."

On the other hand, Apple's market share -- as NPD tracks it in retail and some online sales -- is much larger now than it was 30 months ago. "The success of Leopard will certainly be a function of the installed base [of Macs]," said Swenson. "Unlike Microsoft, Apple has made a point to make its OS so you can upgrade older machines. It's really pretty impressive."

Mac OS X 10.5 will run on all Intel-based and PowerPC G5 Apple computers, as well as on PowerPC G4 systems equipped with a processor running at 867MHz or faster. The OS requires a DVD drive, 9GB of available hard drive space for installation, and 512MB of RAM to run, according to Apple officials. Leopard Server has similar requirements, but demands 1GB of memory and 20GB of available disk space.

Ken Mingis contributed to this report.