iOS4 for everyone released today

Apple will be unleashing iOS4 later today, but you don't have to own an iPhone 4 to get some interesting new goodies.

The free update, which should be available through iTunes at 5pm UK time today, includes a raft of new features for every Apple iDevice from the iPhone 3G through to the 3Gs, and including the second and third generation iPod Touches.

Obviously the iPhone 4 has some new bits of hardware trickery behind its new screen which means that chunks of the new OS won't be included for older models, but there's still plenty of love for those of you unwilling or unable to step into the world of early adoption.

Multitasking
Probably the biggest feature for many Apple detractors, better power management and the new A4 SoC mean that the Iphone 4 can cope with running more than one App at a time. Surprisingly, the 3Gs and latest iPod Touch will also get in on the multi-tasking action.

Bluetooth keyboard support
This one has been a long time coming for iPhone fans, with Apple sticking stubbornly to its 'the on-screen keyboard is plenty good enough' guns. This time, all of the above-mentioned devices will get support. Expect to see lots of iPhone fans toting super-sexy Apple aluminium keyboards on a commuter train near you.

iBooks
Apple has put a lot of effort into turning its iBooks software into the wordy version of iTunes. If electronic books take off in the same way MP3 downloads did, Apple will be well placed to dominate the e-reader market in the same way it has music downloads. As such, iBooks is available across the board.

Video calling
Bit of a no-brainer here. The only iDevice with a front facing camera is the Iphone 4.

iAd
Most users won't see it as a new feature, but Apple's latest money-making scheme, which it says it has developed in order to let software coders make money from free Apps, obviously makes it onto every gadget in our list.

Orientation lock
Only available on the iPhone 4, 3Gs and 3rd gen iPod. Stops the screen flapping about when you're lying in bed reading a book.

Digital camera zoom
Everyone will be able to blow their pics up five times bigger once this is included, but anyone with a decent photo editing application will have the sense not to bother. A gimmick in our book.

Tap to focus
We're a bit confused as to how this works on a camera with a fixed focal length, but we're hearing that tap to focus will work on all devices with a camera.

Compass App support
Will work with any device with a compass... so that's the iPhone 4 and 3Gs only.

Wallpapers for home screen
Most of you will now be able to add your own pics behind all of those application buttons on the home screen. Unless you have a 3G, in which case you'll have to be content with Apple's plain old black background. Frankly, we reckon sticking brightly coloured pics of your kids on the home screen is an invitation to a headache, but it's your phone... you ruin it if you want.

Unified in-box
Everyone gets this, which will allow you to view all of your various mail accounts without having to switch between them. For those of you who have never heard of forwarding.

Noise cancellation
As the iPhone 4 is the only device with a noise cancelling microphone, it's the only one that gets noise cancelling. The rest of us will just have to put up with the outside world.

App-specific location settings
Developers will now be able to let your Apps know exactly where in the world you are using Apple's geo-location APIs. Don't forget... Steve knows where you've been.

Custom dictionary
We'll no longer have to put up with our iPhones trying to mis-spell 'colour' or 'aluminium' or any word ending in 'ise'. Now that your dictionaries can be customized... d'oh!

Categorised App folders
With about a bazillion Apps available on iTunes, your home screen can get a bit overcrowded. App folders will put an end to all of that on all of our five devices. Drag one App onto another similar one and your iDevice will cleverly suggest a folder name, or you can choose your own.

Rotate and resize photos
Does what it says on the tin and works on all five gadgets. Especially handy if you're on one of these new-fangled limited data plans and want to send someone a quick snap. You'll be able to specify whether you want to send it as a small, medium or large file.

App gifting
Across the board. Buy an App and send it to your mates. Ker-ching!

Persistent Wi-fi
Better power management in the iPhone 4's custom A4 chip will be a boon when it comes to keeping your Wi-fi connection always on, but it remains to be seen whether this one will be a flyer on the older models, all of which are included. Apple reckons the iOS4 update will keep things in check but we'll be watching this one closely.

All game support
Apple is keen not to have a two-tier environment when it comes to games but some of the older hardware just can't keep up with the new kids on the block. The 3G and the 2nd generation Touch will be left out of some of the gaming fun.

So there you have it. It's an essential, and most importantly, free update. Go and get it in... oh, about an hour. We'll be there in the queue.

We'll have a full review of iOS4 once we've had a proper fiddle with it and tried to make it break.