UPDATE: Leopard is now shipping with new Macs as well.

Apple releases worldwide its new operating system iteration, Mac OS X Leopard 10.5, this Friday.

Copies of the system which were pre-ordered [1] from online retail stores have started being shipped to customers. The new operating system is available at most physical retail locations, including Apple's own stores where special events have been organized at the occasion.

Among Leopard's main features are Time Machine, a totally redesigned Finder and Desktop, Spaces (multi-desktop), QuickLook (very fast and powerful file previews right from the Finder) among many others.

Official reviewers, who received their copies a few days ago where overall very positive on Apple's new oeprating system:

- David Pogue (NYT [2]): "Leopard is powerful, polished and carefully conceived. Happy surprises, and very few disappointments, lie around every corner."
- Walt Mossberg (WSJ [3]) : "Upgrade of Apple's OS Isn't Revolutionary, But It Beats Microsoft's"
- Edward Baig (USA Today [4]) : "Leopard, Apple's new Mac operating system, hits all the right spots".

Leopard was initially planed for a June introduction, but Apple announced it would release this major upgrade on October.

Apple's new operating system has been available for pre-order at some online retailers for a since June and it appears this iteration of Mac OS X is far more succesful than any other Mac OS X release.

Analysts expect the release of Leopard to boost Mac sales during the quarter and add between $140 and $240 million to the company's quarterly revenue.

Amazon, which offers the Single-user [5] version for $109 and the Family Pack [6] version for $189, lists both versions in the top selling [7] Software list this week at, respectively rank #1 and #2, where Vista stands far behind at which ranks #49.