iCloud: everything you need to know

MobileMe is dead. Long live iCloud.

That's was the resounding message from Steve Jobs' keynote speech at Apple's Worldwide Developers Conference in June – an event that also saw the announcement of OS X 10.7 Lion and iOS 5 for iPhone, iPad and iPod.

The changes wrought by iCloud are fundamental to the way all these devices will work together in future. In a nutshell, Apple is using push technology – first pioneered by the BlackBerry smartphone and then adopted by the iPhone – and has widened its appeal with a whole raft of new features for OS X and iOS that could easily change the way you use them in future.

What is iCloud?

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The biggest change is that the push technology used by iCloud means you'll no longer have to synchronise your Mac with your other Apple kit using the MobileMe synchronisation settings found in System Preferences; it will just happen automatically.

Need to change your partner's mobile phone number? Change it in Address Book on your Mac and that change will be pushed to the Contacts app on your iPhone, iPod and iPad in an instant. You won't even need to do a thing.

However, the there's a whole lot more to the way iCloud works. The aim of this feature is to tell you about each one and how it will affect the way you use your Mac and other devices. Let's start with the basics.

If you use MobileMe and Mail, then you'll know all about push technology already. What's new is that it has spread to iCal and Address Book, so you'll no longer have to worry about synchronising them yourself or frothing in frustration when it doesn't work, or you end up with lots of duplicated content. Steve Jobs admitted during his WWDC keynote that MobileMe was below par – that it "wasn't our finest hour".

Fortunately, iCloud replaces MobileMe's 'It just works... Sometimes' with 'It just works.' It should be a major change for the better.

Arriving in the Autumn alongside iOS 5, iCloud will also give you fully fledged replacements for MobileMe's iDisk and iWork.com (the beta website service Apple launched alongside iWork '09 that enabled you to share your Keynote, Numbers and Pages documents with friends and co-workers, while also acting as a handy backup).

Instead iCloud will now give you iCloud Storage, another push-based cloud computing service that will automatically synchronise any new documents you create on your Mac, iPad, iPod or iPhone to the other devices you own. So no longer will you have to worry that you've left behind a crucial Keynote presentation for work on your Mac at home.

Another new feature of iCloud is the Photo Stream service, which enables you to do with your pictures what you can do with your documents – sync and share them seamlessly and easily using push technology. On the Mac, this feature will be integrated into a future update to iPhoto, but you can already imagine what that means for photos you've take on your iOS device: they'll also automatically appear on your Mac and other Apple devices – and they'll even appear in the My Pictures folder of your work PC, if you have to use one (although the exact details on how this will work have yet to be fleshed out).

One of the most important changes for music fans is that iCloud will also enable you to enjoy content from your iTunes music library anywhere you want it. For Apple has announced iTunes Match, a service that will scan your iTunes library and automatically synchronise it with what's available from the iTunes Store. It will then enable you to add any missing content from the iTunes Store simply by uploading it to iCloud.

What's more is that much of Apple's revamped replacement for MobileMe will be available either cheaply or for free: Contacts, Calendar, Mail and document storage will cost you nothing (with some caveats – more on these later) while iTunes in the Cloud will be a paltry $24.99 (£15.21) a year, although it and iTunes Match are only currently available in the US.

But perhaps the most fundamental change of all is that Apple has finally 'cut the cable' between the Mac and your other Apple devices. Now they will all be able to stay in sync wirelessly using Wi-Fi or 3G.

This gives you the freedom to do whatever you want with whichever device you're using, without either having to tether them to each other using bits of wire, or relying on the vagaries of one of the most unloved corners of the Apple empire: MobileMe.

iCloud release date and beta

iCloud will shop at the same time as iOS 5and some have already received emails welcoming them to iCloud.

The service has gone live for registered Apple developers, with those lucky few able to test the functionality using iOS 5 and Mac OS X Lion.

Feedback so far from the developer community has been mixed with some parties disappointed that full document editing in iWork using iCloud doesn't offer Google Docs-like solution many had hoped for.

iCloud pricing

Apple has announced the pricing tiers for its iCloud service, which was launched in beta for developers on Monday.

The company has already confirmed that it will be offering all iOS and Mac OS X users 5GB of cloud-based storage for free, but if you want a little extra, Apple is offering multiple solutions.

10GB of additional space will cost £14 a year, 20GB extra will be £28 a year, while 50GB of space on top of the free offering will be £70 every 12 months.

However, don't fret, this doesn't include any media files, such as photos from the Photo Stream functionality or music.

iCloud: how and why

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Obviously, being able to synchronise all your stuff seamlessly and using iCloud isn't just about what you'll be able to do. You'll be joined by millions of other Mac, iPhone, iPod and iPad users too.

The numbers speak for themselves: during the WWDC keynote, it was revealed that there are now 54 million active Mac users worldwide, along with 200 million iOS devices. That's an awful lot of data to push around, especially when you factor in iTunes into the Cloud too: you're talking, potentially, about many petabytes of data.

To make all that happen not only requires decent mobile and fixed broadband speeds, it also requires an awful lot of storage, and Apple has been very busy making sure there's plenty to go around.

Firstly, it's invested heavily in upgrading its existing data centres in Cupertino and Newark, California. It has also taken on extra capacity with a seven-year lease at the DuPont Fabros Centre in Santa Clara. Apple's biggest investment, however, has been at Maiden, North Carolina; it's invested $500 million (£304 million) in a new purpose-built data centre on the 255-acres of land it has acquired in the area, with plans already underway to build a second data centre next door.

To make sure iCloud happened, Apple also spent $4.5 million (£2.73 million) buying the iCloud.com domain name from cloud computing company Xcerion. It then splashed an estimated $150 million (£91 million) on making sure it had on board all the major record labels – EMI, Warner, Sony and Universal – so it could launch iTunes in the iCloud.

These are enormous amounts of money in anyone's book. What Apple's competing with, of course, are rival services to iCloud such as Google's Gmail and Amazon's Cloud Drive. Some of these services are available either at a low cost or for free, as well as cloud-based alternatives to iTunes such as Google Music, Spotify and Amazon Cloud Player.

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With so much competition either actually or potentially on the horizon, Apple's investment in iCloud makes perfect sense – especially when you also factor in competition coming from Microsoft, its Xbox Live services and Sony's recently troubled PlayStation network.

There's also the question of what else Apple has up it sleeve. The ability to stream movies, TV shows and other video content was curiously absent from the WWDC keynote, although it's understood that Apple is engaged in bringing these services into iCloud too (something that may be in place for its Autumn launch).

Let's look at some of the iCloud services that already exist in a bit more detail.