The next evolution of Apple’s operating system has arrived, with Mac OS X 10.8 “Mountain Lion” being rolled out around the world with an upgrade fee that’s not much more than a CD.

You can buy a lot of things with twenty dollars, from a DVD or Blu-ray, a bargain bin video game, or some cheap headphones, but today you can now add an operating system to that list, with Apple’s latest update to its Macintosh operating system now available in Australia for $20.99.

Technically the ninth release of Mac OS X since the first version 10.0 or “Cheetah” was released in 2001, the newest incarnation of Mac OS brings with it system wide sharing for photos, videos, and links; the ability to speak at your Mac and have it convert your spoken word to text; a notification bar built into the side; Facebook and iCloud integration; and AirPlay mirroring so you can share the screen of your Mac wirelessly to an Apple TV.

“With iCloud integration, Mountain Lion is even easier to set up, and your important information stays up to date across all your devices so you can keep editing documents, taking notes, creating reminders, and continue conversations whether you started on a Mac, iPhone or iPad,” said Apple’s Philip Schiller, Senior Vice President of Worldwide Marketing at Apple.

Mountain Lion is available now from the App Store, provided you have 10.6.8 or higher on your Mac, for $20.99.

We’ve been testing it for a few hours now and found that while there are quite a few bugs, on the whole, it’s a worthy upgrade for Mac users.

Safari has taken a page out of Google’s Chrome book and ditched the search box altogether, combining it with the URL bar more commonly known in other browsers as the “omni bar”.