The wait is finally over, Apple has released the iOS 5 update for your iPhone 4, iPad 2, iPad, iPhone 3GS, iPhone 3G and iPod touch, bringing with it a host of new features to enjoy.

The new operating system adds around 200 new features in total, with the most exciting of those including a new notification system similar to Android; as well as iMessage, Apple’s answer to RIM’s BlackBerry Messenger service; and Twitter integration, allowing you Tweet from virtually anywhere within the phone. The iPad gets tabbed browsing too. And all devices will now be able to set up Hotmail email natively (rather than through the now absent Microsoft Exchange Server).

Access to iCloud, Apple's cloud storage service is now also available, and you can sign up and sign in after you have upgraded your device. It offers 5GB of storage space completely free, so you can keep documents, books and the like on the Cupertino company's remote servers, ready to be accessed whenever you like and therefore keep your own internal drive free of clutter.

The update is available now through iTunes 10.5 (released on Tuesday) and is free to all Apple customers, although eager users may experience slow downloads due to server overload.

Additionally, those hoping to test out Siri, Apple’s new voice command system, will have to wait until Friday when the iPhone 4S goes on sale. It's an exclusive feature for that device, and will not be part of iOS 5 for any other Apple product.

Check out our iOS 5: What's new? feature to see what else has been added to your iPhone or iPad.

UPDATE: Like many many others, Pocket-lint is feverishly updating its iPads, iPhones and iPod touches too. However, the first screen we've been treated to was one that stated that to update our iPad 2, it needed to back everything up first - apps, contacts, calendar entries, etc - and then restore them. It offers up a timescale for this of "an hour or more". Yikes!

Admittedly, as we have 64GB of stuff on our tablet, it may not take as long on a device not as jam packed. But you have been warned... This could turn out to be a long, long night!

UPDATE 2: iOS 5 error messages hit updaters

What do you think of iOS 5? Let us know in the comments below...