UPDATE: Check out our hands on OS X Lion review.

After a demo in February and a preview version too, we've now got full details on Apple's new OS from the Apple Worldwide Developers' Conference taking place this week in San Francisco

The OS was originally announced back in October 2010, OS X 10.7 Lion has taken some of what makes iOS great and updated for the desktop.

Announcing Lion at the Autumn 2010 keynote, Steve Jobs said the new OS would bring features developed for iOS back to the Mac. "We started with Mac OS X, repurposed it for the iPhone and used it in the iPad as well," he explained. "Now we're bringing some of its ideas back to the Mac."

Today's announcement sees over 250 new features added to the OS, with Apple's Phil Schiller showing off ten key features at WWDC today, including fullscreen applications and multi-touch gestures.

So what OS X 10.7 features will we see?

MacOS X 10.7 Lion UK release date

The Mac OS X Lion 10.7 release date is in July and is available from the Mac AppStore as a 4GB download to all your authorised Macs. Yep, that's right - MacOS X goes disc-free!

MacOS X 10.7 Lion UK price

OS X Lion will cost $29.99 in the US. We're not yet sure what theMacOS X 10.7 Lion UK pricing will be, but we'd expect it to cost £29.

MacOS X 10.7 Lion multi-touch

Lion will be fully multi-touch compatible - all Macs now have multi-touch trackpads while for desktop Macs there's also the Magic Trackpad of course. Mac sales are three quarters notebooks at the moment. The scrollbars in Mac OS X Lion.

Scrollbars simply disappear when you are using gestures, while there's tap-to-zoom, pinching and two-finger swiping. Apple's Phil Schiller says it works "with an incredible, physical realism never been possible in a PC operating system before."

Mac OS X 10.7 Lion is inspired by iOS

There's a new Launchpad in iOS - this is an app launcher that works just like the homescreen in iOS.When you open Launchpad, open windows fade away to be replaced by a grid of application icons, just like you see on your iPad, iPhone or iPod touch. You can rearrange their position by dragging icons to different locations, and group them in virtual folders. And as with iOS, multiple pages of apps can be navigated with a swipe gesture.

Mac OS X 10.7 Lion fullscreen apps

Another feature making its way from iOS to Mac OS is fullscreen applications. With a single click, apps written to take advantage of this feature can fill the entire screen, with no borders or distractions. You can swipe between fullscreen applications and the desktop to use your apps that are not being viewed fullscreen.

Naturally, iLife and OS X-native apps such as iCal, iPhoto, Preview and Mail will have a fullscreen option, and system-wide support allows third party developers to include the feature in their own applications.

Mac OS X 10.7 Lion Mission Control

Mission Control combines Exposé, Spaces and Dashboard into a single feature, giving an overview of everything that's open on your Mac. Mission Control groups open windows according to the application in which they're running, making it much easier to find what you're looking for. As such, thumbnails of Spaces-style virtual desktops and fullscreen apps are shown across the top of the screen, along with the Dashboard. You can swipe between apps even in full screen and exit them using a control in the top right.

Mac OS X 10.7 Lion auto-save

The way OS X saves your work has undergone a revision, with two new features added for Lion. Instead of pressing Command+S every couple of minutes, saving is automatic in OS X 10.7.

It does more than simply save a backup copy as you go, like Microsoft Word and TextEdit do already. Instead, it saves the changes that have been made to a document instead of saving the file in its entirety, so it doesn't waste disk space. You can lock a document to prevent changes being auto-saved, and documents are automatically locked after two weeks.

The Auto Save feature is only available in applications written to take advantage of it, so remember to manually save documents created in non-autosaving apps.

Mac OS X 10.7 Lion Versions

The second new save feature, Versions, creates a history of a document as you work on it. A copy is automatically saved every hour and each time you open it (as well as manually whenever you wish). You can revert to a saved version of your document using a Time Machine-like interface, or simply open an older version and copy something you regret editing out, pasting it into the current document. You can access the different versions of the document via the document's name in the title bar.

Mac OS X 10.7 Lion Resume

If you've ever put off installing a software update as you didn't want the hassle of restarting your Mac while in the middle of something, you'll definitely welcome Lion's new Resume feature. When a Lion Mac restarts, it returns to exactly the same state it was in before it shut down.

Running applications relaunch and open windows reopen. It's so comprehensive that if you highlighted text in an open document or app, it's highlighted again on restart. This will prove incredibly useful, and a major timesaver; no need to save your work, close everything down and then relaunch it all after boot-up. With Lion, it's all done automatically.

Like fullscreen apps and Auto Save, Resume is only available in (to use Apple's term) "apps that have been developed to work with Lion". Third-party developers will no doubt welcome the opportunity to take advantage of these exciting system features, but it remains to be seen how fast software will absorb another level of OS integration.

Mac OS X 10.7 Lion AirDrop

AirDrop is an exciting but limited transfer system that works over Wi-Fi. By clicking the AirDrop icon in your Finder sidebar, you're shown every nearby Mac that's also using AirDrop. If someone in your Address Book runs the Mac, the photo associated with the profile is also shown. To send someone a file or folder, you simply drag it onto his or her name.

AirDrop is peer-to-peer, connecting via Wi-Fi regardless of whether the Macs are on the same network. Transferred files are saved to the recipient's Downloads folder, but only after being accepted; you can't copy something to someone else's Mac without their knowledge and permission.

Unfortunately, AirDrop is only for Macs running Lion. You can't, for example, transfer a file from your Lion iMac to a colleague's Snow Leopard MacBook Pro, and you certainly can't AirDrop to a PC - surely you will be able to use it with iOS in due course though. But if you're in a mixed Mac-PC environment or not all local Macs run the latest version of the operating system, you'll have to stick with Dropbox or USB flash drives.