During Apple’s earnings call yesterday, the company announced that Mac OS X Lion would become available today, and sure enough it has.

The OS was demoed at Apple’s Worldwide Developers Conference in early June, when the company said that Mac has outgrown the industry every quarter for the last five years with sales at 3/4 those of notebooks. Yesterday in the new earnings report, Apple said it sold 3.95 million Macs last quarter – up 14% from the same quarter a year ago. Mac sales, the company said were driven largely by Macbook Pro and Macbook Air.

Mac OS X Lion is the 8th major release of the OS, and has over 250 new features, as well as 3,000 new developer APIs.

It features multi-touch gestures and fluid animations that let you interact directly with content on the scree. New gestures include momentum scrolling, tapping or pinching your fingers to zoom in on a web page or image, and swiping left or right to turn a page or switch between full screen apps.

All new Mac notebooks will now ship with multi-touch trackpads and desktop Macs can use Apple’s Magic Trackpad.

The Mission Control feature combines Exposé, full screen apps, Dashboard and Spaces.You can swipe to get your desktop to zoom out to display open windows grouped by app thumbnails of your full screen apps and your Dashboard.

The Launchpad feature makes it easier to find and launch apps, and with a multi-touch gesture, all of your apps are displayed in a full screen layout. You can organize apps into any order or into folders and swipe through unlimited pages of apps.

There is a also a redesigned Mail app with widescreen layout. It has a new conversations feature that groups related messages into a scrollable timeline. It also has a new search reassure that lets you refine searches and suggests matches by person, subject, and label as you type. The app inludes support for Microsoft Exchange 2010.

Mac OS X Lion also includes Resume, which lets you bring apps back to how you left them when you restart or relaunch the app. In addition to that, apps will automatically save as you work. A feature called Versions records the history of your documents as you create them, and gives you a way to browse, revert, and copy/paste from previous versions.

An AirDrop feature lets you find nearby Macs and set up P2P wireless connections.

Snow Leopard users can upgrade fro $29.99. The upgrade is about 4GB (the size of an HD movie from the iTunes store). It’s available by download through the Mac App Store.

MacRumors reports that Apple has also updated its MacBook Air line with Sandy Bridge, Thunderbolt and Backlit keyboards.