The cat's out of the bag: During Apple's third-quarter financial earnings call Tuesday, chief financial officer Peter Oppenheimer announced that Lion would debut Wednesday on the Mac App Store. The OS update will cost £20.99.

Lion is the seventh iteration of Apple's Mac operating system, OS X, and brings a host of new features to the Mac, including window management utility Mission Control; app organizer Launchpad; full-screen mode for applications; state-saving utility Resume; Auto Save and Versions; AirDrop for local file sharing; a whole slew of updates to existing Apple applications, and over 250 other features.

Lion will be available Wednesday for £20.99 exclusively from the Mac App Store for users running OS X 10.6.6 or later using Core 2 Duo systems or later. Users on Intel Macs powered by a Core Solo or Core Duo processor will not be able to run this version of the OS.

Currently, we've written up information on readying your Mac for Lion, new features you can look forward to in both your apps and within the system, and what to do if you rely on Power-PC apps. To keep up-to-date with all Macworld.com's coverage, bookmark our information center on all things Lion.