What is it?
It's the fourth version of Android's mobile operating system (www. android.com). It was announced on 19 October, alongside the Samsung Galaxy Nexus phone, which runs the OS.
What are its new features?
The key element of Ice Cream Sandwich is that it will run on tablet PCs and phones, unlike its predecessor Android 3.0 (Honeycomb), which was specially made for tablets. This means that all the impressive features that tablet users could enjoy with Honeycomb will be made available for phone users, too.
To mark this, Google has created the new Roboto font, which has been specially designed for high-resolution phone screens. Google says it "improves readability and brings a polished, modern feel to the user interface".
Android 4.0 also has new buttons at the bottom of the screen in some apps that take users to other areas of the phone, such as contacts. The Gmail tool has also been redesigned and modified. And Android 4.0 is the first version of the OS that lets you use the Chrome browser.
What new apps are there?
There are several, the most useful being Android Beam, which uses Near Field Technology to let you share web pages, games, apps and You Tube videos just by tapping phones with another user.
The Camera app has several new features, including built-in face detection, which locates and focuses on faces. You can also take photos at full video resolution just by tapping the screen, even while the video records. The Gallery app has been redesigned, and now contains a photo editor that lets you perform a range of tasks, such as removing the red-eye effect.
There's also the new People app that makes it easier to contact friends and family by phone and text, and on social media services such as Google+ and Twitter.
Which phones can use it?
The first phone to use Android 4.0 is Samsung's Galaxy Nexus (www. google.com/nexus), which will be available in the UK in November. It has a 4.65in screen with 720p resolution, a 1.2GHz dual core processor, 1GB RAM (double what you get in the iPhone 4S) and a 5-megapixel rear-facing camera. It also has a 1.3-megapixel front-facing camera that can be used to unlock the phone with Face Unlock, Android's new facial-recognition feature. It's a button less phone- all actions are performed by touching the screen. Many experts have been impressed by the Nexus; with the website Know Your Mobile calling it the "best Google phone yet" (http://bit.ly/ nexus278).
How much does the Nexus cost?
It's expensive. The cheapest deal so far, announced by Phones4U (www.phones4u.co.uk), is a two-year contract costing £41 per month, if you pay £29.05 up front. That's a total cost of £1.013.05 over two years. You can also get it for free if you subscribe to a £46-a-month contract for two years, at an overall cost of £1,104.
Vodafone, Three and 02 will also offer the Nexus, but prices hadn't been announced at the time of writing. We don't expect them to be any cheaper than £40 a month, though. A SIM-free Nexus is likely to cost around £500.
Can older phones use Android 4.0?
Android 4.0 will also come to other high-end Android phones, including the Nexus S, but it's unlikely to appear on the cheaper models, which use Android 2.3 (Gingerbread).
Why the tasty name?
Every new version of Android is named, in alphabetical order, after a dessert. After Cupcake, Donut and Éclair came Froyo (2.2), Gingerbread (2.3) and Honeycomb (3.0). Place your bets now for what 'J' will be.