So I’ve been sharing a link around for e past few days and thought I’d just crack on and do an article myself.

Anybody running Mac OSX is able to get iOS 4.0 on their iDevices NOW! No need to wait for the 21st June, no need to register as an iPhone developer and no need to install X Code on your machine.

Apple may change things, so please make sure you backup and please don’t blame me if anything goes wrong. All you need to do is update iTunes to 9.2, download the iOS 4.0 ipsw package and the GM is the same version that’ll be pushed as a software update in two weeks.

How do I do it?:

1. First things, first – Download and install iTunes 9.2 (Mac only, download links here, here, or here).

2. Now download the iOS 4.0 Golden Master, making sure you get the right pakage for your device:

• If you have an iPhone 3GS, download this.
• If you have an iPhone 3G, then you need this one.
• iPod Touch 3G, get yours here.
• And finally if you have the iPod Touch 2G, download this.

3. How to install iOS 4.0:

• Plug in your iOS device, and open up iTunes. Let it sync one last time and make sure you backup.
• In iTunes, alt+click on the ‘restore’ button (for those that asked, ALT is the key to the left of COMMAND/APPLE), and then when asked to locate the file, select the IPSW file we just moved to your desktop.
• iTunes will now install iOS 4.0 to your iPhone or iPod Touch! You can start fresh or restore that backup you just did.

That’s it. iBooks is slowly being pushed to 4.0 users, so be patient and you’ll have that soon.

Also, Apple are now allowing 4.0-compatible updates to be submitted to the App Store. So shortly, we’ll start seeing apps taking full use of the new API’s including multitasking!

Once the update is pushed to users on the 21st June, you probably won’t have to update. This is the same copy. Finally, please remember that I’m just sharing this information. Don’t blame me if something goes wrong. The best option if you brick your device is just go to an Apple Store, tell a Genius you don’t know what went wrong, and they’re likely to swap it for you. (This happened to me last year with 3.0 and they kindly swapped iPhones).

Enjoy, have fun and share your findings with me here, twitter or facebook!