OS X Mountain Lion now available: New operating system released on Apple Store for $19.99

Apple launched OS X Mountain Lion today, the latest version of its operating system.

Click here to go to the Apple Store where it is available for $19.99

Some Apple Store employees were told to plan an all-nighter last night for its release.

Also, Apple's quarterly earnings report is scheduled for the 24th. Last year, the current Mac system, Lion, was announced during a July earnings report and released the next day.

At its WWDC developers conference last month in San Francisco, Apple said that Mountain Lion will have 200 new features.

They'll include iMessages, the texting feature already available on mobile devices, speech-to-text dictation and predictive "smart search" in the Safari browser.

The new Mountain Lion system also adds something called Power Nap, a feature that keeps your laptop up to date while it sleeps by automatically refreshing mail, contacts and other apps.

Game Center will be another adaptation coming from the mobile iOS system, giving gamers a central place to find games and opponents -- a stab by Apple at gaining relevance in a desktop gaming space that is still dominated by Microsoft with its Xbox Live network.

Time: OS X Mountain Lion's 10 Most Important New Features

Developers already were given a final trial version of Mountain Lion, the so-called "gold master," at last month's conference.

Apple's transitioning of some mobile features to its desktop system suggests that the company is at least mindful of Microsoft's aggressive move to create a seamless experience between smartphones, tablets and desktops.

Microsoft's Windows 8 system, planned for later this year, is designed to work with touchscreen devices as well as on laptops and desktops. The computing giant has struggled in the mobile space, particularly with tablets, but early reviews suggest the new system will mark Redmond's most serious challenge yet to Apple's dominance.